Merge tag 'trace-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "There was a lot of clean ups and minor fixes.  One of those clean ups
  was to the trace_seq code.  It also removed the return values to the
  trace_seq_*() functions and use trace_seq_has_overflowed() to see if
  the buffer filled up or not.  This is similar to work being done to
  the seq_file code as well in another tree.

  Some of the other goodies include:

   - Added some "!" (NOT) logic to the tracing filter.

   - Fixed the frame pointer logic to the x86_64 mcount trampolines

   - Added the logic for dynamic trampolines on !CONFIG_PREEMPT systems.
     That is, the ftrace trampoline can be dynamically allocated and be
     called directly by functions that only have a single hook to them"

* tag 'trace-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (55 commits)
  tracing: Truncated output is better than nothing
  tracing: Add additional marks to signal very large time deltas
  Documentation: describe trace_buf_size parameter more accurately
  tracing: Allow NOT to filter AND and OR clauses
  tracing: Add NOT to filtering logic
  ftrace/fgraph/x86: Have prepare_ftrace_return() take ip as first parameter
  ftrace/x86: Get rid of ftrace_caller_setup
  ftrace/x86: Have save_mcount_regs macro also save stack frames if needed
  ftrace/x86: Add macro MCOUNT_REG_SIZE for amount of stack used to save mcount regs
  ftrace/x86: Simplify save_mcount_regs on getting RIP
  ftrace/x86: Have save_mcount_regs store RIP in %rdi for first parameter
  ftrace/x86: Rename MCOUNT_SAVE_FRAME and add more detailed comments
  ftrace/x86: Move MCOUNT_SAVE_FRAME out of header file
  ftrace/x86: Have static tracing also use ftrace_caller_setup
  ftrace/x86: Have static function tracing always test for function graph
  kprobes: Add IPMODIFY flag to kprobe_ftrace_ops
  ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict
  kprobes/ftrace: Recover original IP if pre_handler doesn't change it
  tracing/trivial: Fix typos and make an int into a bool
  tracing: Deletion of an unnecessary check before iput()
  ...

kernel/trace/blktrace.c

@@ -1142,9 +1142,9 @@ static void get_pdu_remap(const struct trace_entry *ent,
 	r->sector_from = be64_to_cpu(sector_from);
 }
 
-typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
+typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
 
-static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
+static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
 {
 	char rwbs[RWBS_LEN];
 	unsigned long long ts  = iter->ts;
@@ -1154,33 +1154,33 @@ static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
 
 	fill_rwbs(rwbs, t);
 
-	return trace_seq_printf(&iter->seq,
-				"%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
-				MAJOR(t->device), MINOR(t->device), iter->cpu,
-				secs, nsec_rem, iter->ent->pid, act, rwbs);
+	trace_seq_printf(&iter->seq,
+			 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
+			 MAJOR(t->device), MINOR(t->device), iter->cpu,
+			 secs, nsec_rem, iter->ent->pid, act, rwbs);
 }
 
-static int blk_log_action(struct trace_iterator *iter, const char *act)
+static void blk_log_action(struct trace_iterator *iter, const char *act)
 {
 	char rwbs[RWBS_LEN];
 	const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
 
 	fill_rwbs(rwbs, t);
-	return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
-				MAJOR(t->device), MINOR(t->device), act, rwbs);
+	trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
+			 MAJOR(t->device), MINOR(t->device), act, rwbs);
 }
 
-static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
 {
 	const unsigned char *pdu_buf;
 	int pdu_len;
-	int i, end, ret;
+	int i, end;
 
 	pdu_buf = pdu_start(ent);
 	pdu_len = te_blk_io_trace(ent)->pdu_len;
 
 	if (!pdu_len)
-		return 1;
+		return;
 
 	/* find the last zero that needs to be printed */
 	for (end = pdu_len - 1; end >= 0; end--)
@@ -1188,119 +1188,107 @@ static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
 			break;
 	end++;
 
-	if (!trace_seq_putc(s, '('))
-		return 0;
+	trace_seq_putc(s, '(');
 
 	for (i = 0; i < pdu_len; i++) {
 
-		ret = trace_seq_printf(s, "%s%02x",
-				       i == 0 ? "" : " ", pdu_buf[i]);
-		if (!ret)
-			return ret;
+		trace_seq_printf(s, "%s%02x",
+				 i == 0 ? "" : " ", pdu_buf[i]);
 
 		/*
 		 * stop when the rest is just zeroes and indicate so
 		 * with a ".." appended
 		 */
-		if (i == end && end != pdu_len - 1)
-			return trace_seq_puts(s, " ..) ");
+		if (i == end && end != pdu_len - 1) {
+			trace_seq_puts(s, " ..) ");
+			return;
+		}
 	}
 
-	return trace_seq_puts(s, ") ");
+	trace_seq_puts(s, ") ");
 }
 
-static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
 {
 	char cmd[TASK_COMM_LEN];
 
 	trace_find_cmdline(ent->pid, cmd);
 
 	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
-		int ret;
-
-		ret = trace_seq_printf(s, "%u ", t_bytes(ent));
-		if (!ret)
-			return 0;
-		ret = blk_log_dump_pdu(s, ent);
-		if (!ret)
-			return 0;
-		return trace_seq_printf(s, "[%s]\n", cmd);
+		trace_seq_printf(s, "%u ", t_bytes(ent));
+		blk_log_dump_pdu(s, ent);
+		trace_seq_printf(s, "[%s]\n", cmd);
 	} else {
 		if (t_sec(ent))
-			return trace_seq_printf(s, "%llu + %u [%s]\n",
+			trace_seq_printf(s, "%llu + %u [%s]\n",
 						t_sector(ent), t_sec(ent), cmd);
-		return trace_seq_printf(s, "[%s]\n", cmd);
+		else
+			trace_seq_printf(s, "[%s]\n", cmd);
 	}
 }
 
-static int blk_log_with_error(struct trace_seq *s,
+static void blk_log_with_error(struct trace_seq *s,
 			      const struct trace_entry *ent)
 {
 	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
-		int ret;
-
-		ret = blk_log_dump_pdu(s, ent);
-		if (ret)
-			return trace_seq_printf(s, "[%d]\n", t_error(ent));
-		return 0;
+		blk_log_dump_pdu(s, ent);
+		trace_seq_printf(s, "[%d]\n", t_error(ent));
 	} else {
 		if (t_sec(ent))
-			return trace_seq_printf(s, "%llu + %u [%d]\n",
-						t_sector(ent),
-						t_sec(ent), t_error(ent));
-		return trace_seq_printf(s, "%llu [%d]\n",
-					t_sector(ent), t_error(ent));
+			trace_seq_printf(s, "%llu + %u [%d]\n",
+					 t_sector(ent),
+					 t_sec(ent), t_error(ent));
+		else
+			trace_seq_printf(s, "%llu [%d]\n",
+					 t_sector(ent), t_error(ent));
 	}
 }
 
-static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
 {
 	struct blk_io_trace_remap r = { .device_from = 0, };
 
 	get_pdu_remap(ent, &r);
-	return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
-				t_sector(ent), t_sec(ent),
-				MAJOR(r.device_from), MINOR(r.device_from),
-				(unsigned long long)r.sector_from);
+	trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
+			 t_sector(ent), t_sec(ent),
+			 MAJOR(r.device_from), MINOR(r.device_from),
+			 (unsigned long long)r.sector_from);
 }
 
-static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
 {
 	char cmd[TASK_COMM_LEN];
 
 	trace_find_cmdline(ent->pid, cmd);
 
-	return trace_seq_printf(s, "[%s]\n", cmd);
+	trace_seq_printf(s, "[%s]\n", cmd);
 }
 
-static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
 {
 	char cmd[TASK_COMM_LEN];
 
 	trace_find_cmdline(ent->pid, cmd);
 
-	return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
+	trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
 }
 
-static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
 {
 	char cmd[TASK_COMM_LEN];
 
 	trace_find_cmdline(ent->pid, cmd);
 
-	return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
-				get_pdu_int(ent), cmd);
+	trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
+			 get_pdu_int(ent), cmd);
 }
 
-static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
 {
-	int ret;
 	const struct blk_io_trace *t = te_blk_io_trace(ent);
 
-	ret = trace_seq_putmem(s, t + 1, t->pdu_len);
-	if (ret)
-		return trace_seq_putc(s, '\n');
-	return ret;
+	trace_seq_putmem(s, t + 1, t->pdu_len);
+	trace_seq_putc(s, '\n');
 }
 
 /*
@@ -1339,7 +1327,7 @@ static void blk_tracer_reset(struct trace_array *tr)
 
 static const struct {
 	const char *act[2];
-	int	   (*print)(struct trace_seq *s, const struct trace_entry *ent);
+	void	   (*print)(struct trace_seq *s, const struct trace_entry *ent);
 } what2act[] = {
 	[__BLK_TA_QUEUE]	= {{  "Q", "queue" },	   blk_log_generic },
 	[__BLK_TA_BACKMERGE]	= {{  "M", "backmerge" },  blk_log_generic },
@@ -1364,7 +1352,6 @@ static enum print_line_t print_one_line(struct trace_iterator *iter,
 	struct trace_seq *s = &iter->seq;
 	const struct blk_io_trace *t;
 	u16 what;
-	int ret;
 	bool long_act;
 	blk_log_action_t *log_action;
 
@@ -1374,21 +1361,18 @@ static enum print_line_t print_one_line(struct trace_iterator *iter,
 	log_action = classic ? &blk_log_action_classic : &blk_log_action;
 
 	if (t->action == BLK_TN_MESSAGE) {
-		ret = log_action(iter, long_act ? "message" : "m");
-		if (ret)
-			ret = blk_log_msg(s, iter->ent);
-		goto out;
+		log_action(iter, long_act ? "message" : "m");
+		blk_log_msg(s, iter->ent);
 	}
 
 	if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
-		ret = trace_seq_printf(s, "Unknown action %x\n", what);
+		trace_seq_printf(s, "Unknown action %x\n", what);
 	else {
-		ret = log_action(iter, what2act[what].act[long_act]);
-		if (ret)
-			ret = what2act[what].print(s, iter->ent);
+		log_action(iter, what2act[what].act[long_act]);
+		what2act[what].print(s, iter->ent);
 	}
-out:
-	return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+
+	return trace_handle_return(s);
 }
 
 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
@@ -1397,7 +1381,7 @@ static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
 	return print_one_line(iter, false);
 }
 
-static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
+static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
 {
 	struct trace_seq *s = &iter->seq;
 	struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
@@ -1407,18 +1391,18 @@ static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
 		.time     = iter->ts,
 	};
 
-	if (!trace_seq_putmem(s, &old, offset))
-		return 0;
-	return trace_seq_putmem(s, &t->sector,
-				sizeof(old) - offset + t->pdu_len);
+	trace_seq_putmem(s, &old, offset);
+	trace_seq_putmem(s, &t->sector,
+			 sizeof(old) - offset + t->pdu_len);
 }
 
 static enum print_line_t
 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
 			     struct trace_event *event)
 {
-	return blk_trace_synthesize_old_trace(iter) ?
-			TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+	blk_trace_synthesize_old_trace(iter);
+
+	return trace_handle_return(&iter->seq);
 }
 
 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)

kernel/trace/ftrace.c

@@ -387,6 +387,8 @@ static int remove_ftrace_list_ops(struct ftrace_ops **list,
 	return ret;
 }
 
+static void ftrace_update_trampoline(struct ftrace_ops *ops);
+
 static int __register_ftrace_function(struct ftrace_ops *ops)
 {
 	if (ops->flags & FTRACE_OPS_FL_DELETED)
@@ -416,9 +418,13 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
 		if (control_ops_alloc(ops))
 			return -ENOMEM;
 		add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
+		/* The control_ops needs the trampoline update */
+		ops = &control_ops;
 	} else
 		add_ftrace_ops(&ftrace_ops_list, ops);
 
+	ftrace_update_trampoline(ops);
+
 	if (ftrace_enabled)
 		update_ftrace_function();
 
@@ -565,13 +571,13 @@ static int function_stat_cmp(void *p1, void *p2)
 static int function_stat_headers(struct seq_file *m)
 {
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	seq_printf(m, "  Function                               "
-		   "Hit    Time            Avg             s^2\n"
-		      "  --------                               "
-		   "---    ----            ---             ---\n");
+	seq_puts(m, "  Function                               "
+		 "Hit    Time            Avg             s^2\n"
+		    "  --------                               "
+		 "---    ----            ---             ---\n");
 #else
-	seq_printf(m, "  Function                               Hit\n"
-		      "  --------                               ---\n");
+	seq_puts(m, "  Function                               Hit\n"
+		    "  --------                               ---\n");
 #endif
 	return 0;
 }
@@ -598,7 +604,7 @@ static int function_stat_show(struct seq_file *m, void *v)
 	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	seq_printf(m, "    ");
+	seq_puts(m, "    ");
 	avg = rec->time;
 	do_div(avg, rec->counter);
 
@@ -1111,6 +1117,43 @@ static struct ftrace_ops global_ops = {
 					  FTRACE_OPS_FL_INITIALIZED,
 };
 
+/*
+ * This is used by __kernel_text_address() to return true if the
+ * address is on a dynamically allocated trampoline that would
+ * not return true for either core_kernel_text() or
+ * is_module_text_address().
+ */
+bool is_ftrace_trampoline(unsigned long addr)
+{
+	struct ftrace_ops *op;
+	bool ret = false;
+
+	/*
+	 * Some of the ops may be dynamically allocated,
+	 * they are freed after a synchronize_sched().
+	 */
+	preempt_disable_notrace();
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		/*
+		 * This is to check for dynamically allocated trampolines.
+		 * Trampolines that are in kernel text will have
+		 * core_kernel_text() return true.
+		 */
+		if (op->trampoline && op->trampoline_size)
+			if (addr >= op->trampoline &&
+			    addr < op->trampoline + op->trampoline_size) {
+				ret = true;
+				goto out;
+			}
+	} while_for_each_ftrace_op(op);
+
+ out:
+	preempt_enable_notrace();
+
+	return ret;
+}
+
 struct ftrace_page {
 	struct ftrace_page	*next;
 	struct dyn_ftrace	*records;
@@ -1315,6 +1358,9 @@ ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
 static void
 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
 
+static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
+				       struct ftrace_hash *new_hash);
+
 static int
 ftrace_hash_move(struct ftrace_ops *ops, int enable,
 		 struct ftrace_hash **dst, struct ftrace_hash *src)
@@ -1325,8 +1371,13 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
 	struct ftrace_hash *new_hash;
 	int size = src->count;
 	int bits = 0;
+	int ret;
 	int i;
 
+	/* Reject setting notrace hash on IPMODIFY ftrace_ops */
+	if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
+		return -EINVAL;
+
 	/*
 	 * If the new source is empty, just free dst and assign it
 	 * the empty_hash.
@@ -1360,6 +1411,16 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
 	}
 
 update:
+	/* Make sure this can be applied if it is IPMODIFY ftrace_ops */
+	if (enable) {
+		/* IPMODIFY should be updated only when filter_hash updating */
+		ret = ftrace_hash_ipmodify_update(ops, new_hash);
+		if (ret < 0) {
+			free_ftrace_hash(new_hash);
+			return ret;
+		}
+	}
+
 	/*
 	 * Remove the current set, update the hash and add
 	 * them back.
@@ -1724,6 +1785,114 @@ static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
 	ftrace_hash_rec_update_modify(ops, filter_hash, 1);
 }
 
+/*
+ * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
+ * or no-needed to update, -EBUSY if it detects a conflict of the flag
+ * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
+ * Note that old_hash and new_hash has below meanings
+ *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
+ *  - If the hash is EMPTY_HASH, it hits nothing
+ *  - Anything else hits the recs which match the hash entries.
+ */
+static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
+					 struct ftrace_hash *old_hash,
+					 struct ftrace_hash *new_hash)
+{
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec, *end = NULL;
+	int in_old, in_new;
+
+	/* Only update if the ops has been registered */
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return 0;
+
+	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
+		return 0;
+
+	/*
+	 * Since the IPMODIFY is a very address sensitive action, we do not
+	 * allow ftrace_ops to set all functions to new hash.
+	 */
+	if (!new_hash || !old_hash)
+		return -EINVAL;
+
+	/* Update rec->flags */
+	do_for_each_ftrace_rec(pg, rec) {
+		/* We need to update only differences of filter_hash */
+		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
+		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
+		if (in_old == in_new)
+			continue;
+
+		if (in_new) {
+			/* New entries must ensure no others are using it */
+			if (rec->flags & FTRACE_FL_IPMODIFY)
+				goto rollback;
+			rec->flags |= FTRACE_FL_IPMODIFY;
+		} else /* Removed entry */
+			rec->flags &= ~FTRACE_FL_IPMODIFY;
+	} while_for_each_ftrace_rec();
+
+	return 0;
+
+rollback:
+	end = rec;
+
+	/* Roll back what we did above */
+	do_for_each_ftrace_rec(pg, rec) {
+		if (rec == end)
+			goto err_out;
+
+		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
+		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
+		if (in_old == in_new)
+			continue;
+
+		if (in_new)
+			rec->flags &= ~FTRACE_FL_IPMODIFY;
+		else
+			rec->flags |= FTRACE_FL_IPMODIFY;
+	} while_for_each_ftrace_rec();
+
+err_out:
+	return -EBUSY;
+}
+
+static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
+{
+	struct ftrace_hash *hash = ops->func_hash->filter_hash;
+
+	if (ftrace_hash_empty(hash))
+		hash = NULL;
+
+	return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
+}
+
+/* Disabling always succeeds */
+static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
+{
+	struct ftrace_hash *hash = ops->func_hash->filter_hash;
+
+	if (ftrace_hash_empty(hash))
+		hash = NULL;
+
+	__ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
+}
+
+static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
+				       struct ftrace_hash *new_hash)
+{
+	struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
+
+	if (ftrace_hash_empty(old_hash))
+		old_hash = NULL;
+
+	if (ftrace_hash_empty(new_hash))
+		new_hash = NULL;
+
+	return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
+}
+
 static void print_ip_ins(const char *fmt, unsigned char *p)
 {
 	int i;
@@ -1734,10 +1903,13 @@ static void print_ip_ins(const char *fmt, unsigned char *p)
 		printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 }
 
+static struct ftrace_ops *
+ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
+
 /**
  * ftrace_bug - report and shutdown function tracer
  * @failed: The failed type (EFAULT, EINVAL, EPERM)
- * @ip: The address that failed
+ * @rec: The record that failed
  *
  * The arch code that enables or disables the function tracing
  * can call ftrace_bug() when it has detected a problem in
@@ -1746,8 +1918,10 @@ static void print_ip_ins(const char *fmt, unsigned char *p)
  * EINVAL - if what is read at @ip is not what was expected
  * EPERM - if the problem happens on writting to the @ip address
  */
-void ftrace_bug(int failed, unsigned long ip)
+void ftrace_bug(int failed, struct dyn_ftrace *rec)
 {
+	unsigned long ip = rec ? rec->ip : 0;
+
 	switch (failed) {
 	case -EFAULT:
 		FTRACE_WARN_ON_ONCE(1);
@@ -1759,7 +1933,7 @@ void ftrace_bug(int failed, unsigned long ip)
 		pr_info("ftrace failed to modify ");
 		print_ip_sym(ip);
 		print_ip_ins(" actual: ", (unsigned char *)ip);
-		printk(KERN_CONT "\n");
+		pr_cont("\n");
 		break;
 	case -EPERM:
 		FTRACE_WARN_ON_ONCE(1);
@@ -1771,6 +1945,24 @@ void ftrace_bug(int failed, unsigned long ip)
 		pr_info("ftrace faulted on unknown error ");
 		print_ip_sym(ip);
 	}
+	if (rec) {
+		struct ftrace_ops *ops = NULL;
+
+		pr_info("ftrace record flags: %lx\n", rec->flags);
+		pr_cont(" (%ld)%s", ftrace_rec_count(rec),
+			rec->flags & FTRACE_FL_REGS ? " R" : "  ");
+		if (rec->flags & FTRACE_FL_TRAMP_EN) {
+			ops = ftrace_find_tramp_ops_any(rec);
+			if (ops)
+				pr_cont("\ttramp: %pS",
+					(void *)ops->trampoline);
+			else
+				pr_cont("\ttramp: ERROR!");
+
+		}
+		ip = ftrace_get_addr_curr(rec);
+		pr_cont(" expected tramp: %lx\n", ip);
+	}
 }
 
 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
@@ -2093,7 +2285,7 @@ void __weak ftrace_replace_code(int enable)
 	do_for_each_ftrace_rec(pg, rec) {
 		failed = __ftrace_replace_code(rec, enable);
 		if (failed) {
-			ftrace_bug(failed, rec->ip);
+			ftrace_bug(failed, rec);
 			/* Stop processing */
 			return;
 		}
@@ -2175,17 +2367,14 @@ struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
 static int
 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 {
-	unsigned long ip;
 	int ret;
 
-	ip = rec->ip;
-
 	if (unlikely(ftrace_disabled))
 		return 0;
 
 	ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
 	if (ret) {
-		ftrace_bug(ret, ip);
+		ftrace_bug(ret, rec);
 		return 0;
 	}
 	return 1;
@@ -2320,6 +2509,10 @@ static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
 static ftrace_func_t saved_ftrace_func;
 static int ftrace_start_up;
 
+void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
+{
+}
+
 static void control_ops_free(struct ftrace_ops *ops)
 {
 	free_percpu(ops->disabled);
@@ -2369,6 +2562,15 @@ static int ftrace_startup(struct ftrace_ops *ops, int command)
 	 */
 	ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
 
+	ret = ftrace_hash_ipmodify_enable(ops);
+	if (ret < 0) {
+		/* Rollback registration process */
+		__unregister_ftrace_function(ops);
+		ftrace_start_up--;
+		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
+		return ret;
+	}
+
 	ftrace_hash_rec_enable(ops, 1);
 
 	ftrace_startup_enable(command);
@@ -2397,6 +2599,8 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
 	 */
 	WARN_ON_ONCE(ftrace_start_up < 0);
 
+	/* Disabling ipmodify never fails */
+	ftrace_hash_ipmodify_disable(ops);
 	ftrace_hash_rec_disable(ops, 1);
 
 	ops->flags &= ~FTRACE_OPS_FL_ENABLED;
@@ -2471,6 +2675,8 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
 	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
 		schedule_on_each_cpu(ftrace_sync);
 
+		arch_ftrace_trampoline_free(ops);
+
 		if (ops->flags & FTRACE_OPS_FL_CONTROL)
 			control_ops_free(ops);
 	}
@@ -2623,7 +2829,7 @@ static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
 			if (ftrace_start_up && cnt) {
 				int failed = __ftrace_replace_code(p, 1);
 				if (failed)
-					ftrace_bug(failed, p->ip);
+					ftrace_bug(failed, p);
 			}
 		}
 	}
@@ -2948,6 +3154,22 @@ static void t_stop(struct seq_file *m, void *p)
 	mutex_unlock(&ftrace_lock);
 }
 
+void * __weak
+arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
+{
+	return NULL;
+}
+
+static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
+				struct dyn_ftrace *rec)
+{
+	void *ptr;
+
+	ptr = arch_ftrace_trampoline_func(ops, rec);
+	if (ptr)
+		seq_printf(m, " ->%pS", ptr);
+}
+
 static int t_show(struct seq_file *m, void *v)
 {
 	struct ftrace_iterator *iter = m->private;
@@ -2958,9 +3180,9 @@ static int t_show(struct seq_file *m, void *v)
 
 	if (iter->flags & FTRACE_ITER_PRINTALL) {
 		if (iter->flags & FTRACE_ITER_NOTRACE)
-			seq_printf(m, "#### no functions disabled ####\n");
+			seq_puts(m, "#### no functions disabled ####\n");
 		else
-			seq_printf(m, "#### all functions enabled ####\n");
+			seq_puts(m, "#### all functions enabled ####\n");
 		return 0;
 	}
 
@@ -2971,22 +3193,25 @@ static int t_show(struct seq_file *m, void *v)
 
 	seq_printf(m, "%ps", (void *)rec->ip);
 	if (iter->flags & FTRACE_ITER_ENABLED) {
-		seq_printf(m, " (%ld)%s",
-			   ftrace_rec_count(rec),
-			   rec->flags & FTRACE_FL_REGS ? " R" : "  ");
-		if (rec->flags & FTRACE_FL_TRAMP_EN) {
-			struct ftrace_ops *ops;
+		struct ftrace_ops *ops = NULL;
 
+		seq_printf(m, " (%ld)%s%s",
+			   ftrace_rec_count(rec),
+			   rec->flags & FTRACE_FL_REGS ? " R" : "  ",
+			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ");
+		if (rec->flags & FTRACE_FL_TRAMP_EN) {
 			ops = ftrace_find_tramp_ops_any(rec);
 			if (ops)
 				seq_printf(m, "\ttramp: %pS",
 					   (void *)ops->trampoline);
 			else
-				seq_printf(m, "\ttramp: ERROR!");
+				seq_puts(m, "\ttramp: ERROR!");
+
 		}
+		add_trampoline_func(m, ops, rec);
 	}	
 
-	seq_printf(m, "\n");
+	seq_putc(m, '\n');
 
 	return 0;
 }
@@ -3020,9 +3245,6 @@ ftrace_enabled_open(struct inode *inode, struct file *file)
 {
 	struct ftrace_iterator *iter;
 
-	if (unlikely(ftrace_disabled))
-		return -ENODEV;
-
 	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
 	if (iter) {
 		iter->pg = ftrace_pages_start;
@@ -3975,6 +4197,9 @@ static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
 
+static unsigned long save_global_trampoline;
+static unsigned long save_global_flags;
+
 static int __init set_graph_function(char *str)
 {
 	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
@@ -4183,9 +4408,9 @@ static int g_show(struct seq_file *m, void *v)
 		struct ftrace_graph_data *fgd = m->private;
 
 		if (fgd->table == ftrace_graph_funcs)
-			seq_printf(m, "#### all functions enabled ####\n");
+			seq_puts(m, "#### all functions enabled ####\n");
 		else
-			seq_printf(m, "#### no functions disabled ####\n");
+			seq_puts(m, "#### no functions disabled ####\n");
 		return 0;
 	}
 
@@ -4696,6 +4921,32 @@ void __init ftrace_init(void)
 	ftrace_disabled = 1;
 }
 
+/* Do nothing if arch does not support this */
+void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
+{
+}
+
+static void ftrace_update_trampoline(struct ftrace_ops *ops)
+{
+
+/*
+ * Currently there's no safe way to free a trampoline when the kernel
+ * is configured with PREEMPT. That is because a task could be preempted
+ * when it jumped to the trampoline, it may be preempted for a long time
+ * depending on the system load, and currently there's no way to know
+ * when it will be off the trampoline. If the trampoline is freed
+ * too early, when the task runs again, it will be executing on freed
+ * memory and crash.
+ */
+#ifdef CONFIG_PREEMPT
+	/* Currently, only non dynamic ops can have a trampoline */
+	if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
+		return;
+#endif
+
+	arch_ftrace_update_trampoline(ops);
+}
+
 #else
 
 static struct ftrace_ops global_ops = {
@@ -4738,6 +4989,10 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 	return 1;
 }
 
+static void ftrace_update_trampoline(struct ftrace_ops *ops)
+{
+}
+
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 __init void ftrace_init_global_array_ops(struct trace_array *tr)
@@ -5075,12 +5330,12 @@ static int fpid_show(struct seq_file *m, void *v)
 	const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
 
 	if (v == (void *)1) {
-		seq_printf(m, "no pid\n");
+		seq_puts(m, "no pid\n");
 		return 0;
 	}
 
 	if (fpid->pid == ftrace_swapper_pid)
-		seq_printf(m, "swapper tasks\n");
+		seq_puts(m, "swapper tasks\n");
 	else
 		seq_printf(m, "%u\n", pid_vnr(fpid->pid));
 
@@ -5293,6 +5548,7 @@ static struct ftrace_ops graph_ops = {
 				   FTRACE_OPS_FL_STUB,
 #ifdef FTRACE_GRAPH_TRAMP_ADDR
 	.trampoline		= FTRACE_GRAPH_TRAMP_ADDR,
+	/* trampoline_size is only needed for dynamically allocated tramps */
 #endif
 	ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
 };
@@ -5522,7 +5778,6 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 	update_function_graph_func();
 
 	ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
-
 out:
 	mutex_unlock(&ftrace_lock);
 	return ret;
@@ -5543,6 +5798,17 @@ void unregister_ftrace_graph(void)
 	unregister_pm_notifier(&ftrace_suspend_notifier);
 	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+	/*
+	 * Function graph does not allocate the trampoline, but
+	 * other global_ops do. We need to reset the ALLOC_TRAMP flag
+	 * if one was used.
+	 */
+	global_ops.trampoline = save_global_trampoline;
+	if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
+		global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
+#endif
+
  out:
 	mutex_unlock(&ftrace_lock);
 }

kernel/trace/ring_buffer.c

@@ -34,21 +34,19 @@ static void update_pages_handler(struct work_struct *work);
  */
 int ring_buffer_print_entry_header(struct trace_seq *s)
 {
-	int ret;
+	trace_seq_puts(s, "# compressed entry header\n");
+	trace_seq_puts(s, "\ttype_len    :    5 bits\n");
+	trace_seq_puts(s, "\ttime_delta  :   27 bits\n");
+	trace_seq_puts(s, "\tarray       :   32 bits\n");
+	trace_seq_putc(s, '\n');
+	trace_seq_printf(s, "\tpadding     : type == %d\n",
+			 RINGBUF_TYPE_PADDING);
+	trace_seq_printf(s, "\ttime_extend : type == %d\n",
+			 RINGBUF_TYPE_TIME_EXTEND);
+	trace_seq_printf(s, "\tdata max type_len  == %d\n",
+			 RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
 
-	ret = trace_seq_puts(s, "# compressed entry header\n");
-	ret = trace_seq_puts(s, "\ttype_len    :    5 bits\n");
-	ret = trace_seq_puts(s, "\ttime_delta  :   27 bits\n");
-	ret = trace_seq_puts(s, "\tarray       :   32 bits\n");
-	ret = trace_seq_putc(s, '\n');
-	ret = trace_seq_printf(s, "\tpadding     : type == %d\n",
-			       RINGBUF_TYPE_PADDING);
-	ret = trace_seq_printf(s, "\ttime_extend : type == %d\n",
-			       RINGBUF_TYPE_TIME_EXTEND);
-	ret = trace_seq_printf(s, "\tdata max type_len  == %d\n",
-			       RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
-
-	return ret;
+	return !trace_seq_has_overflowed(s);
 }
 
 /*
@@ -419,32 +417,31 @@ static inline int test_time_stamp(u64 delta)
 int ring_buffer_print_page_header(struct trace_seq *s)
 {
 	struct buffer_data_page field;
-	int ret;
 
-	ret = trace_seq_printf(s, "\tfield: u64 timestamp;\t"
-			       "offset:0;\tsize:%u;\tsigned:%u;\n",
-			       (unsigned int)sizeof(field.time_stamp),
-			       (unsigned int)is_signed_type(u64));
+	trace_seq_printf(s, "\tfield: u64 timestamp;\t"
+			 "offset:0;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)sizeof(field.time_stamp),
+			 (unsigned int)is_signed_type(u64));
 
-	ret = trace_seq_printf(s, "\tfield: local_t commit;\t"
-			       "offset:%u;\tsize:%u;\tsigned:%u;\n",
-			       (unsigned int)offsetof(typeof(field), commit),
-			       (unsigned int)sizeof(field.commit),
-			       (unsigned int)is_signed_type(long));
+	trace_seq_printf(s, "\tfield: local_t commit;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), commit),
+			 (unsigned int)sizeof(field.commit),
+			 (unsigned int)is_signed_type(long));
 
-	ret = trace_seq_printf(s, "\tfield: int overwrite;\t"
-			       "offset:%u;\tsize:%u;\tsigned:%u;\n",
-			       (unsigned int)offsetof(typeof(field), commit),
-			       1,
-			       (unsigned int)is_signed_type(long));
+	trace_seq_printf(s, "\tfield: int overwrite;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), commit),
+			 1,
+			 (unsigned int)is_signed_type(long));
 
-	ret = trace_seq_printf(s, "\tfield: char data;\t"
-			       "offset:%u;\tsize:%u;\tsigned:%u;\n",
-			       (unsigned int)offsetof(typeof(field), data),
-			       (unsigned int)BUF_PAGE_SIZE,
-			       (unsigned int)is_signed_type(char));
+	trace_seq_printf(s, "\tfield: char data;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), data),
+			 (unsigned int)BUF_PAGE_SIZE,
+			 (unsigned int)is_signed_type(char));
 
-	return ret;
+	return !trace_seq_has_overflowed(s);
 }
 
 struct rb_irq_work {

kernel/trace/trace.c

@@ -155,10 +155,11 @@ __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
 
 static int __init stop_trace_on_warning(char *str)
 {
-	__disable_trace_on_warning = 1;
+	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
+		__disable_trace_on_warning = 1;
 	return 1;
 }
-__setup("traceoff_on_warning=", stop_trace_on_warning);
+__setup("traceoff_on_warning", stop_trace_on_warning);
 
 static int __init boot_alloc_snapshot(char *str)
 {
@@ -2158,9 +2159,7 @@ __trace_array_vprintk(struct ring_buffer *buffer,
 		goto out;
 	}
 
-	len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
-	if (len > TRACE_BUF_SIZE)
-		goto out;
+	len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
 
 	local_save_flags(flags);
 	size = sizeof(*entry) + len + 1;
@@ -2171,8 +2170,7 @@ __trace_array_vprintk(struct ring_buffer *buffer,
 	entry = ring_buffer_event_data(event);
 	entry->ip = ip;
 
-	memcpy(&entry->buf, tbuffer, len);
-	entry->buf[len] = '\0';
+	memcpy(&entry->buf, tbuffer, len + 1);
 	if (!call_filter_check_discard(call, entry, buffer, event)) {
 		__buffer_unlock_commit(buffer, event);
 		ftrace_trace_stack(buffer, flags, 6, pc);
@@ -2509,14 +2507,14 @@ get_total_entries(struct trace_buffer *buf,
 
 static void print_lat_help_header(struct seq_file *m)
 {
-	seq_puts(m, "#                  _------=> CPU#            \n");
-	seq_puts(m, "#                 / _-----=> irqs-off        \n");
-	seq_puts(m, "#                | / _----=> need-resched    \n");
-	seq_puts(m, "#                || / _---=> hardirq/softirq \n");
-	seq_puts(m, "#                ||| / _--=> preempt-depth   \n");
-	seq_puts(m, "#                |||| /     delay             \n");
-	seq_puts(m, "#  cmd     pid   ||||| time  |   caller      \n");
-	seq_puts(m, "#     \\   /      |||||  \\    |   /           \n");
+	seq_puts(m, "#                  _------=> CPU#            \n"
+		    "#                 / _-----=> irqs-off        \n"
+		    "#                | / _----=> need-resched    \n"
+		    "#                || / _---=> hardirq/softirq \n"
+		    "#                ||| / _--=> preempt-depth   \n"
+		    "#                |||| /     delay            \n"
+		    "#  cmd     pid   ||||| time  |   caller      \n"
+		    "#     \\   /      |||||  \\    |   /         \n");
 }
 
 static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
@@ -2533,20 +2531,20 @@ static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
 static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
 {
 	print_event_info(buf, m);
-	seq_puts(m, "#           TASK-PID   CPU#      TIMESTAMP  FUNCTION\n");
-	seq_puts(m, "#              | |       |          |         |\n");
+	seq_puts(m, "#           TASK-PID   CPU#      TIMESTAMP  FUNCTION\n"
+		    "#              | |       |          |         |\n");
 }
 
 static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
 {
 	print_event_info(buf, m);
-	seq_puts(m, "#                              _-----=> irqs-off\n");
-	seq_puts(m, "#                             / _----=> need-resched\n");
-	seq_puts(m, "#                            | / _---=> hardirq/softirq\n");
-	seq_puts(m, "#                            || / _--=> preempt-depth\n");
-	seq_puts(m, "#                            ||| /     delay\n");
-	seq_puts(m, "#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION\n");
-	seq_puts(m, "#              | |       |   ||||       |         |\n");
+	seq_puts(m, "#                              _-----=> irqs-off\n"
+		    "#                             / _----=> need-resched\n"
+		    "#                            | / _---=> hardirq/softirq\n"
+		    "#                            || / _--=> preempt-depth\n"
+		    "#                            ||| /     delay\n"
+		    "#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION\n"
+		    "#              | |       |   ||||       |         |\n");
 }
 
 void
@@ -2649,24 +2647,21 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
 	event = ftrace_find_event(entry->type);
 
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-		if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
-			if (!trace_print_lat_context(iter))
-				goto partial;
-		} else {
-			if (!trace_print_context(iter))
-				goto partial;
-		}
+		if (iter->iter_flags & TRACE_FILE_LAT_FMT)
+			trace_print_lat_context(iter);
+		else
+			trace_print_context(iter);
 	}
 
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
+
 	if (event)
 		return event->funcs->trace(iter, sym_flags, event);
 
-	if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
-		goto partial;
+	trace_seq_printf(s, "Unknown type %d\n", entry->type);
 
-	return TRACE_TYPE_HANDLED;
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
@@ -2677,22 +2672,20 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
 
 	entry = iter->ent;
 
-	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-		if (!trace_seq_printf(s, "%d %d %llu ",
-				      entry->pid, iter->cpu, iter->ts))
-			goto partial;
-	}
+	if (trace_flags & TRACE_ITER_CONTEXT_INFO)
+		trace_seq_printf(s, "%d %d %llu ",
+				 entry->pid, iter->cpu, iter->ts);
+
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
 
 	event = ftrace_find_event(entry->type);
 	if (event)
 		return event->funcs->raw(iter, 0, event);
 
-	if (!trace_seq_printf(s, "%d ?\n", entry->type))
-		goto partial;
+	trace_seq_printf(s, "%d ?\n", entry->type);
 
-	return TRACE_TYPE_HANDLED;
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
@@ -2705,9 +2698,11 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
 	entry = iter->ent;
 
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-		SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
-		SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
-		SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
+		SEQ_PUT_HEX_FIELD(s, entry->pid);
+		SEQ_PUT_HEX_FIELD(s, iter->cpu);
+		SEQ_PUT_HEX_FIELD(s, iter->ts);
+		if (trace_seq_has_overflowed(s))
+			return TRACE_TYPE_PARTIAL_LINE;
 	}
 
 	event = ftrace_find_event(entry->type);
@@ -2717,9 +2712,9 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
 			return ret;
 	}
 
-	SEQ_PUT_FIELD_RET(s, newline);
+	SEQ_PUT_FIELD(s, newline);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
@@ -2731,9 +2726,11 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
 	entry = iter->ent;
 
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-		SEQ_PUT_FIELD_RET(s, entry->pid);
-		SEQ_PUT_FIELD_RET(s, iter->cpu);
-		SEQ_PUT_FIELD_RET(s, iter->ts);
+		SEQ_PUT_FIELD(s, entry->pid);
+		SEQ_PUT_FIELD(s, iter->cpu);
+		SEQ_PUT_FIELD(s, iter->ts);
+		if (trace_seq_has_overflowed(s))
+			return TRACE_TYPE_PARTIAL_LINE;
 	}
 
 	event = ftrace_find_event(entry->type);
@@ -2779,10 +2776,12 @@ enum print_line_t print_trace_line(struct trace_iterator *iter)
 {
 	enum print_line_t ret;
 
-	if (iter->lost_events &&
-	    !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
-				 iter->cpu, iter->lost_events))
-		return TRACE_TYPE_PARTIAL_LINE;
+	if (iter->lost_events) {
+		trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
+				 iter->cpu, iter->lost_events);
+		if (trace_seq_has_overflowed(&iter->seq))
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
 
 	if (iter->trace && iter->trace->print_line) {
 		ret = iter->trace->print_line(iter);
@@ -2860,44 +2859,44 @@ static void test_ftrace_alive(struct seq_file *m)
 {
 	if (!ftrace_is_dead())
 		return;
-	seq_printf(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
-	seq_printf(m, "#          MAY BE MISSING FUNCTION EVENTS\n");
+	seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
+		    "#          MAY BE MISSING FUNCTION EVENTS\n");
 }
 
 #ifdef CONFIG_TRACER_MAX_TRACE
 static void show_snapshot_main_help(struct seq_file *m)
 {
-	seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
-	seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
-	seq_printf(m, "#                      Takes a snapshot of the main buffer.\n");
-	seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n");
-	seq_printf(m, "#                      (Doesn't have to be '2' works with any number that\n");
-	seq_printf(m, "#                       is not a '0' or '1')\n");
+	seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
+		    "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
+		    "#                      Takes a snapshot of the main buffer.\n"
+		    "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
+		    "#                      (Doesn't have to be '2' works with any number that\n"
+		    "#                       is not a '0' or '1')\n");
 }
 
 static void show_snapshot_percpu_help(struct seq_file *m)
 {
-	seq_printf(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
+	seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
-	seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
-	seq_printf(m, "#                      Takes a snapshot of the main buffer for this cpu.\n");
+	seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
+		    "#                      Takes a snapshot of the main buffer for this cpu.\n");
 #else
-	seq_printf(m, "# echo 1 > snapshot : Not supported with this kernel.\n");
-	seq_printf(m, "#                     Must use main snapshot file to allocate.\n");
+	seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
+		    "#                     Must use main snapshot file to allocate.\n");
 #endif
-	seq_printf(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
-	seq_printf(m, "#                      (Doesn't have to be '2' works with any number that\n");
-	seq_printf(m, "#                       is not a '0' or '1')\n");
+	seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
+		    "#                      (Doesn't have to be '2' works with any number that\n"
+		    "#                       is not a '0' or '1')\n");
 }
 
 static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
 {
 	if (iter->tr->allocated_snapshot)
-		seq_printf(m, "#\n# * Snapshot is allocated *\n#\n");
+		seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
 	else
-		seq_printf(m, "#\n# * Snapshot is freed *\n#\n");
+		seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
 
-	seq_printf(m, "# Snapshot commands:\n");
+	seq_puts(m, "# Snapshot commands:\n");
 	if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
 		show_snapshot_main_help(m);
 	else
@@ -3251,7 +3250,7 @@ static int t_show(struct seq_file *m, void *v)
 	if (!t)
 		return 0;
 
-	seq_printf(m, "%s", t->name);
+	seq_puts(m, t->name);
 	if (t->next)
 		seq_putc(m, ' ');
 	else
@@ -5749,10 +5748,10 @@ ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
 
 	seq_printf(m, "%ps:", (void *)ip);
 
-	seq_printf(m, "snapshot");
+	seq_puts(m, "snapshot");
 
 	if (count == -1)
-		seq_printf(m, ":unlimited\n");
+		seq_puts(m, ":unlimited\n");
 	else
 		seq_printf(m, ":count=%ld\n", count);
 

kernel/trace/trace.h

@@ -14,6 +14,7 @@
 #include <linux/trace_seq.h>
 #include <linux/ftrace_event.h>
 #include <linux/compiler.h>
+#include <linux/trace_seq.h>
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 #include <asm/unistd.h>		/* For NR_SYSCALLS	     */
@@ -569,15 +570,6 @@ void trace_init_global_iter(struct trace_iterator *iter);
 
 void tracing_iter_reset(struct trace_iterator *iter, int cpu);
 
-void tracing_sched_switch_trace(struct trace_array *tr,
-				struct task_struct *prev,
-				struct task_struct *next,
-				unsigned long flags, int pc);
-
-void tracing_sched_wakeup_trace(struct trace_array *tr,
-				struct task_struct *wakee,
-				struct task_struct *cur,
-				unsigned long flags, int pc);
 void trace_function(struct trace_array *tr,
 		    unsigned long ip,
 		    unsigned long parent_ip,
@@ -597,9 +589,6 @@ void set_graph_array(struct trace_array *tr);
 
 void tracing_start_cmdline_record(void);
 void tracing_stop_cmdline_record(void);
-void tracing_sched_switch_assign_trace(struct trace_array *tr);
-void tracing_stop_sched_switch_record(void);
-void tracing_start_sched_switch_record(void);
 int register_tracer(struct tracer *type);
 int is_tracing_stopped(void);
 
@@ -719,6 +708,8 @@ enum print_line_t print_trace_line(struct trace_iterator *iter);
 
 extern unsigned long trace_flags;
 
+extern char trace_find_mark(unsigned long long duration);
+
 /* Standard output formatting function used for function return traces */
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
@@ -737,7 +728,7 @@ extern unsigned long trace_flags;
 extern enum print_line_t
 print_graph_function_flags(struct trace_iterator *iter, u32 flags);
 extern void print_graph_headers_flags(struct seq_file *s, u32 flags);
-extern enum print_line_t
+extern void
 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
 extern void graph_trace_open(struct trace_iterator *iter);
 extern void graph_trace_close(struct trace_iterator *iter);

kernel/trace/trace_branch.c

@@ -151,22 +151,21 @@ static enum print_line_t trace_branch_print(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	if (trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
-			     field->correct ? "  ok  " : " MISS ",
-			     field->func,
-			     field->file,
-			     field->line))
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
+			 field->correct ? "  ok  " : " MISS ",
+			 field->func,
+			 field->file,
+			 field->line);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(&iter->seq);
 }
 
 static void branch_print_header(struct seq_file *s)
 {
 	seq_puts(s, "#           TASK-PID    CPU#    TIMESTAMP  CORRECT"
-		"  FUNC:FILE:LINE\n");
-	seq_puts(s, "#              | |       |          |         |   "
-		"    |\n");
+		    "  FUNC:FILE:LINE\n"
+		    "#              | |       |          |         |   "
+		    "    |\n");
 }
 
 static struct trace_event_functions trace_branch_funcs = {
@@ -233,12 +232,12 @@ extern unsigned long __stop_annotated_branch_profile[];
 
 static int annotated_branch_stat_headers(struct seq_file *m)
 {
-	seq_printf(m, " correct incorrect  %% ");
-	seq_printf(m, "       Function                "
-			      "  File              Line\n"
-			      " ------- ---------  - "
-			      "       --------                "
-			      "  ----              ----\n");
+	seq_puts(m, " correct incorrect  % "
+		    "       Function                "
+		    "  File              Line\n"
+		    " ------- ---------  - "
+		    "       --------                "
+		    "  ----              ----\n");
 	return 0;
 }
 
@@ -274,7 +273,7 @@ static int branch_stat_show(struct seq_file *m, void *v)
 
 	seq_printf(m, "%8lu %8lu ",  p->correct, p->incorrect);
 	if (percent < 0)
-		seq_printf(m, "  X ");
+		seq_puts(m, "  X ");
 	else
 		seq_printf(m, "%3ld ", percent);
 	seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
@@ -362,12 +361,12 @@ extern unsigned long __stop_branch_profile[];
 
 static int all_branch_stat_headers(struct seq_file *m)
 {
-	seq_printf(m, "   miss      hit    %% ");
-	seq_printf(m, "       Function                "
-			      "  File              Line\n"
-			      " ------- ---------  - "
-			      "       --------                "
-			      "  ----              ----\n");
+	seq_puts(m, "   miss      hit    % "
+		    "       Function                "
+		    "  File              Line\n"
+		    " ------- ---------  - "
+		    "       --------                "
+		    "  ----              ----\n");
 	return 0;
 }
 

kernel/trace/trace_events.c

@@ -918,7 +918,7 @@ static int f_show(struct seq_file *m, void *v)
 	case FORMAT_HEADER:
 		seq_printf(m, "name: %s\n", ftrace_event_name(call));
 		seq_printf(m, "ID: %d\n", call->event.type);
-		seq_printf(m, "format:\n");
+		seq_puts(m, "format:\n");
 		return 0;
 
 	case FORMAT_FIELD_SEPERATOR:
@@ -1988,7 +1988,7 @@ event_enable_print(struct seq_file *m, unsigned long ip,
 		   ftrace_event_name(data->file->event_call));
 
 	if (data->count == -1)
-		seq_printf(m, ":unlimited\n");
+		seq_puts(m, ":unlimited\n");
 	else
 		seq_printf(m, ":count=%ld\n", data->count);
 

kernel/trace/trace_events_filter.c

@@ -45,6 +45,7 @@ enum filter_op_ids
 	OP_GT,
 	OP_GE,
 	OP_BAND,
+	OP_NOT,
 	OP_NONE,
 	OP_OPEN_PAREN,
 };
@@ -67,6 +68,7 @@ static struct filter_op filter_ops[] = {
 	{ OP_GT,	">",		5 },
 	{ OP_GE,	">=",		5 },
 	{ OP_BAND,	"&",		6 },
+	{ OP_NOT,	"!",		6 },
 	{ OP_NONE,	"OP_NONE",	0 },
 	{ OP_OPEN_PAREN, "(",		0 },
 };
@@ -85,6 +87,7 @@ enum {
 	FILT_ERR_MISSING_FIELD,
 	FILT_ERR_INVALID_FILTER,
 	FILT_ERR_IP_FIELD_ONLY,
+	FILT_ERR_ILLEGAL_NOT_OP,
 };
 
 static char *err_text[] = {
@@ -101,6 +104,7 @@ static char *err_text[] = {
 	"Missing field name and/or value",
 	"Meaningless filter expression",
 	"Only 'ip' field is supported for function trace",
+	"Illegal use of '!'",
 };
 
 struct opstack_op {
@@ -139,6 +143,7 @@ struct pred_stack {
 	int			index;
 };
 
+/* If not of not match is equal to not of not, then it is a match */
 #define DEFINE_COMPARISON_PRED(type)					\
 static int filter_pred_##type(struct filter_pred *pred, void *event)	\
 {									\
@@ -166,7 +171,7 @@ static int filter_pred_##type(struct filter_pred *pred, void *event)	\
 		break;							\
 	}								\
 									\
-	return match;							\
+	return !!match == !pred->not;					\
 }
 
 #define DEFINE_EQUALITY_PRED(size)					\
@@ -484,9 +489,10 @@ static int process_ops(struct filter_pred *preds,
 		if (!WARN_ON_ONCE(!pred->fn))
 			match = pred->fn(pred, rec);
 		if (!!match == type)
-			return match;
+			break;
 	}
-	return match;
+	/* If not of not match is equal to not of not, then it is a match */
+	return !!match == !op->not;
 }
 
 struct filter_match_preds_data {
@@ -735,10 +741,10 @@ static int filter_set_pred(struct event_filter *filter,
 		 * then this op can be folded.
 		 */
 		if (left->index & FILTER_PRED_FOLD &&
-		    (left->op == dest->op ||
+		    ((left->op == dest->op && !left->not) ||
 		     left->left == FILTER_PRED_INVALID) &&
 		    right->index & FILTER_PRED_FOLD &&
-		    (right->op == dest->op ||
+		    ((right->op == dest->op && !right->not) ||
 		     right->left == FILTER_PRED_INVALID))
 			dest->index |= FILTER_PRED_FOLD;
 
@@ -1028,7 +1034,7 @@ static int init_pred(struct filter_parse_state *ps,
 	}
 
 	if (pred->op == OP_NE)
-		pred->not = 1;
+		pred->not ^= 1;
 
 	pred->fn = fn;
 	return 0;
@@ -1590,6 +1596,17 @@ static int replace_preds(struct ftrace_event_call *call,
 			continue;
 		}
 
+		if (elt->op == OP_NOT) {
+			if (!n_preds || operand1 || operand2) {
+				parse_error(ps, FILT_ERR_ILLEGAL_NOT_OP, 0);
+				err = -EINVAL;
+				goto fail;
+			}
+			if (!dry_run)
+				filter->preds[n_preds - 1].not ^= 1;
+			continue;
+		}
+
 		if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) {
 			parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
 			err = -ENOSPC;

kernel/trace/trace_events_trigger.c

@@ -373,7 +373,7 @@ event_trigger_print(const char *name, struct seq_file *m,
 {
 	long count = (long)data;
 
-	seq_printf(m, "%s", name);
+	seq_puts(m, name);
 
 	if (count == -1)
 		seq_puts(m, ":unlimited");
@@ -383,7 +383,7 @@ event_trigger_print(const char *name, struct seq_file *m,
 	if (filter_str)
 		seq_printf(m, " if %s\n", filter_str);
 	else
-		seq_puts(m, "\n");
+		seq_putc(m, '\n');
 
 	return 0;
 }
@@ -1105,7 +1105,7 @@ event_enable_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 	if (data->filter_str)
 		seq_printf(m, " if %s\n", data->filter_str);
 	else
-		seq_puts(m, "\n");
+		seq_putc(m, '\n');
 
 	return 0;
 }

kernel/trace/trace_functions.c

@@ -261,37 +261,74 @@ static struct tracer function_trace __tracer_data =
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-static int update_count(void **data)
+static void update_traceon_count(void **data, bool on)
 {
-	unsigned long *count = (long *)data;
+	long *count = (long *)data;
+	long old_count = *count;
 
-	if (!*count)
-		return 0;
+	/*
+	 * Tracing gets disabled (or enabled) once per count.
+	 * This function can be called at the same time on multiple CPUs.
+	 * It is fine if both disable (or enable) tracing, as disabling
+	 * (or enabling) the second time doesn't do anything as the
+	 * state of the tracer is already disabled (or enabled).
+	 * What needs to be synchronized in this case is that the count
+	 * only gets decremented once, even if the tracer is disabled
+	 * (or enabled) twice, as the second one is really a nop.
+	 *
+	 * The memory barriers guarantee that we only decrement the
+	 * counter once. First the count is read to a local variable
+	 * and a read barrier is used to make sure that it is loaded
+	 * before checking if the tracer is in the state we want.
+	 * If the tracer is not in the state we want, then the count
+	 * is guaranteed to be the old count.
+	 *
+	 * Next the tracer is set to the state we want (disabled or enabled)
+	 * then a write memory barrier is used to make sure that
+	 * the new state is visible before changing the counter by
+	 * one minus the old counter. This guarantees that another CPU
+	 * executing this code will see the new state before seeing
+	 * the new counter value, and would not do anything if the new
+	 * counter is seen.
+	 *
+	 * Note, there is no synchronization between this and a user
+	 * setting the tracing_on file. But we currently don't care
+	 * about that.
+	 */
+	if (!old_count)
+		return;
 
-	if (*count != -1)
-		(*count)--;
+	/* Make sure we see count before checking tracing state */
+	smp_rmb();
 
-	return 1;
+	if (on == !!tracing_is_on())
+		return;
+
+	if (on)
+		tracing_on();
+	else
+		tracing_off();
+
+	/* unlimited? */
+	if (old_count == -1)
+		return;
+
+	/* Make sure tracing state is visible before updating count */
+	smp_wmb();
+
+	*count = old_count - 1;
 }
 
 static void
 ftrace_traceon_count(unsigned long ip, unsigned long parent_ip, void **data)
 {
-	if (tracing_is_on())
-		return;
-
-	if (update_count(data))
-		tracing_on();
+	update_traceon_count(data, 1);
 }
 
 static void
 ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip, void **data)
 {
-	if (!tracing_is_on())
-		return;
-
-	if (update_count(data))
-		tracing_off();
+	update_traceon_count(data, 0);
 }
 
 static void
@@ -330,11 +367,49 @@ ftrace_stacktrace(unsigned long ip, unsigned long parent_ip, void **data)
 static void
 ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip, void **data)
 {
-	if (!tracing_is_on())
-		return;
+	long *count = (long *)data;
+	long old_count;
+	long new_count;
 
-	if (update_count(data))
-		trace_dump_stack(STACK_SKIP);
+	/*
+	 * Stack traces should only execute the number of times the
+	 * user specified in the counter.
+	 */
+	do {
+
+		if (!tracing_is_on())
+			return;
+
+		old_count = *count;
+
+		if (!old_count)
+			return;
+
+		/* unlimited? */
+		if (old_count == -1) {
+			trace_dump_stack(STACK_SKIP);
+			return;
+		}
+
+		new_count = old_count - 1;
+		new_count = cmpxchg(count, old_count, new_count);
+		if (new_count == old_count)
+			trace_dump_stack(STACK_SKIP);
+
+	} while (new_count != old_count);
+}
+
+static int update_count(void **data)
+{
+	unsigned long *count = (long *)data;
+
+	if (!*count)
+		return 0;
+
+	if (*count != -1)
+		(*count)--;
+
+	return 1;
 }
 
 static void
@@ -361,7 +436,7 @@ ftrace_probe_print(const char *name, struct seq_file *m,
 	seq_printf(m, "%ps:%s", (void *)ip, name);
 
 	if (count == -1)
-		seq_printf(m, ":unlimited\n");
+		seq_puts(m, ":unlimited\n");
 	else
 		seq_printf(m, ":count=%ld\n", count);
 

kernel/trace/trace_functions_graph.c

@@ -107,7 +107,7 @@ enum {
 	FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 };
 
-static enum print_line_t
+static void
 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 		     u32 flags);
 
@@ -483,33 +483,24 @@ static int graph_trace_update_thresh(struct trace_array *tr)
 
 static int max_bytes_for_cpu;
 
-static enum print_line_t
-print_graph_cpu(struct trace_seq *s, int cpu)
+static void print_graph_cpu(struct trace_seq *s, int cpu)
 {
-	int ret;
-
 	/*
 	 * Start with a space character - to make it stand out
 	 * to the right a bit when trace output is pasted into
 	 * email:
 	 */
-	ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 }
 
 #define TRACE_GRAPH_PROCINFO_LENGTH	14
 
-static enum print_line_t
-print_graph_proc(struct trace_seq *s, pid_t pid)
+static void print_graph_proc(struct trace_seq *s, pid_t pid)
 {
 	char comm[TASK_COMM_LEN];
 	/* sign + log10(MAX_INT) + '\0' */
 	char pid_str[11];
 	int spaces = 0;
-	int ret;
 	int len;
 	int i;
 
@@ -524,56 +515,43 @@ print_graph_proc(struct trace_seq *s, pid_t pid)
 		spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 
 	/* First spaces to align center */
-	for (i = 0; i < spaces / 2; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	for (i = 0; i < spaces / 2; i++)
+		trace_seq_putc(s, ' ');
 
-	ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s-%s", comm, pid_str);
 
 	/* Last spaces to align center */
-	for (i = 0; i < spaces - (spaces / 2); i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
-	return TRACE_TYPE_HANDLED;
+	for (i = 0; i < spaces - (spaces / 2); i++)
+		trace_seq_putc(s, ' ');
 }
 
 
-static enum print_line_t
-print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 {
-	if (!trace_seq_putc(s, ' '))
-		return 0;
-
-	return trace_print_lat_fmt(s, entry);
+	trace_seq_putc(s, ' ');
+	trace_print_lat_fmt(s, entry);
 }
 
 /* If the pid changed since the last trace, output this event */
-static enum print_line_t
+static void
 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 {
 	pid_t prev_pid;
 	pid_t *last_pid;
-	int ret;
 
 	if (!data)
-		return TRACE_TYPE_HANDLED;
+		return;
 
 	last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 
 	if (*last_pid == pid)
-		return TRACE_TYPE_HANDLED;
+		return;
 
 	prev_pid = *last_pid;
 	*last_pid = pid;
 
 	if (prev_pid == -1)
-		return TRACE_TYPE_HANDLED;
+		return;
 /*
  * Context-switch trace line:
 
@@ -582,33 +560,12 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
  ------------------------------------------
 
  */
-	ret = trace_seq_puts(s,
-		" ------------------------------------------\n");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = print_graph_cpu(s, cpu);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = print_graph_proc(s, prev_pid);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_seq_puts(s, " => ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = print_graph_proc(s, pid);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_seq_puts(s,
-		"\n ------------------------------------------\n\n");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_puts(s, " ------------------------------------------\n");
+	print_graph_cpu(s, cpu);
+	print_graph_proc(s, prev_pid);
+	trace_seq_puts(s, " => ");
+	print_graph_proc(s, pid);
+	trace_seq_puts(s, "\n ------------------------------------------\n\n");
 }
 
 static struct ftrace_graph_ret_entry *
@@ -682,175 +639,122 @@ get_return_for_leaf(struct trace_iterator *iter,
 	return next;
 }
 
-static int print_graph_abs_time(u64 t, struct trace_seq *s)
+static void print_graph_abs_time(u64 t, struct trace_seq *s)
 {
 	unsigned long usecs_rem;
 
 	usecs_rem = do_div(t, NSEC_PER_SEC);
 	usecs_rem /= 1000;
 
-	return trace_seq_printf(s, "%5lu.%06lu |  ",
-			(unsigned long)t, usecs_rem);
+	trace_seq_printf(s, "%5lu.%06lu |  ",
+			 (unsigned long)t, usecs_rem);
 }
 
-static enum print_line_t
+static void
 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 		enum trace_type type, int cpu, pid_t pid, u32 flags)
 {
-	int ret;
 	struct trace_seq *s = &iter->seq;
+	struct trace_entry *ent = iter->ent;
 
 	if (addr < (unsigned long)__irqentry_text_start ||
 		addr >= (unsigned long)__irqentry_text_end)
-		return TRACE_TYPE_UNHANDLED;
+		return;
 
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 		/* Absolute time */
-		if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
-			ret = print_graph_abs_time(iter->ts, s);
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+			print_graph_abs_time(iter->ts, s);
 
 		/* Cpu */
-		if (flags & TRACE_GRAPH_PRINT_CPU) {
-			ret = print_graph_cpu(s, cpu);
-			if (ret == TRACE_TYPE_PARTIAL_LINE)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		if (flags & TRACE_GRAPH_PRINT_CPU)
+			print_graph_cpu(s, cpu);
 
 		/* Proc */
 		if (flags & TRACE_GRAPH_PRINT_PROC) {
-			ret = print_graph_proc(s, pid);
-			if (ret == TRACE_TYPE_PARTIAL_LINE)
-				return TRACE_TYPE_PARTIAL_LINE;
-			ret = trace_seq_puts(s, " | ");
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
+			print_graph_proc(s, pid);
+			trace_seq_puts(s, " | ");
 		}
+
+		/* Latency format */
+		if (trace_flags & TRACE_ITER_LATENCY_FMT)
+			print_graph_lat_fmt(s, ent);
 	}
 
 	/* No overhead */
-	ret = print_graph_duration(0, s, flags | FLAGS_FILL_START);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
+	print_graph_duration(0, s, flags | FLAGS_FILL_START);
 
 	if (type == TRACE_GRAPH_ENT)
-		ret = trace_seq_puts(s, "==========>");
+		trace_seq_puts(s, "==========>");
 	else
-		ret = trace_seq_puts(s, "<==========");
+		trace_seq_puts(s, "<==========");
 
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = print_graph_duration(0, s, flags | FLAGS_FILL_END);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
-
-	ret = trace_seq_putc(s, '\n');
-
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-	return TRACE_TYPE_HANDLED;
+	print_graph_duration(0, s, flags | FLAGS_FILL_END);
+	trace_seq_putc(s, '\n');
 }
 
-enum print_line_t
+void
 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 {
 	unsigned long nsecs_rem = do_div(duration, 1000);
 	/* log10(ULONG_MAX) + '\0' */
-	char msecs_str[21];
+	char usecs_str[21];
 	char nsecs_str[5];
-	int ret, len;
+	int len;
 	int i;
 
-	sprintf(msecs_str, "%lu", (unsigned long) duration);
+	sprintf(usecs_str, "%lu", (unsigned long) duration);
 
 	/* Print msecs */
-	ret = trace_seq_printf(s, "%s", msecs_str);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s", usecs_str);
 
-	len = strlen(msecs_str);
+	len = strlen(usecs_str);
 
 	/* Print nsecs (we don't want to exceed 7 numbers) */
 	if (len < 7) {
 		size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
 
 		snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
-		ret = trace_seq_printf(s, ".%s", nsecs_str);
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_printf(s, ".%s", nsecs_str);
 		len += strlen(nsecs_str);
 	}
 
-	ret = trace_seq_puts(s, " us ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, " us ");
 
 	/* Print remaining spaces to fit the row's width */
-	for (i = len; i < 7; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
-	return TRACE_TYPE_HANDLED;
+	for (i = len; i < 7; i++)
+		trace_seq_putc(s, ' ');
 }
 
-static enum print_line_t
+static void
 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 		     u32 flags)
 {
-	int ret = -1;
-
 	if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 	    !(trace_flags & TRACE_ITER_CONTEXT_INFO))
-			return TRACE_TYPE_HANDLED;
+		return;
 
 	/* No real adata, just filling the column with spaces */
 	switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
 	case FLAGS_FILL_FULL:
-		ret = trace_seq_puts(s, "              |  ");
-		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_puts(s, "              |  ");
+		return;
 	case FLAGS_FILL_START:
-		ret = trace_seq_puts(s, "  ");
-		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_puts(s, "  ");
+		return;
 	case FLAGS_FILL_END:
-		ret = trace_seq_puts(s, " |");
-		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_puts(s, " |");
+		return;
 	}
 
 	/* Signal a overhead of time execution to the output */
-	if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
-		/* Duration exceeded 100 msecs */
-		if (duration > 100000ULL)
-			ret = trace_seq_puts(s, "! ");
-		/* Duration exceeded 10 msecs */
-		else if (duration > 10000ULL)
-			ret = trace_seq_puts(s, "+ ");
-	}
+	if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
+		trace_seq_printf(s, "%c ", trace_find_mark(duration));
+	else
+		trace_seq_puts(s, "  ");
 
-	/*
-	 * The -1 means we either did not exceed the duration tresholds
-	 * or we dont want to print out the overhead. Either way we need
-	 * to fill out the space.
-	 */
-	if (ret == -1)
-		ret = trace_seq_puts(s, "  ");
-
-	/* Catching here any failure happenned above */
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_print_graph_duration(duration, s);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
-
-	ret = trace_seq_puts(s, "|  ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_print_graph_duration(duration, s);
+	trace_seq_puts(s, "|  ");
 }
 
 /* Case of a leaf function on its call entry */
@@ -864,7 +768,6 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 	struct ftrace_graph_ret *graph_ret;
 	struct ftrace_graph_ent *call;
 	unsigned long long duration;
-	int ret;
 	int i;
 
 	graph_ret = &ret_entry->ret;
@@ -890,22 +793,15 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 	}
 
 	/* Overhead and duration */
-	ret = print_graph_duration(duration, s, flags);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_duration(duration, s, flags);
 
 	/* Function */
-	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
 
-	ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%ps();\n", (void *)call->func);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -915,7 +811,6 @@ print_graph_entry_nested(struct trace_iterator *iter,
 {
 	struct ftrace_graph_ent *call = &entry->graph_ent;
 	struct fgraph_data *data = iter->private;
-	int ret;
 	int i;
 
 	if (data) {
@@ -931,19 +826,15 @@ print_graph_entry_nested(struct trace_iterator *iter,
 	}
 
 	/* No time */
-	ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
+	print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 
 	/* Function */
-	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
 
-	ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
-	if (!ret)
+	trace_seq_printf(s, "%ps() {\n", (void *)call->func);
+
+	if (trace_seq_has_overflowed(s))
 		return TRACE_TYPE_PARTIAL_LINE;
 
 	/*
@@ -953,62 +844,43 @@ print_graph_entry_nested(struct trace_iterator *iter,
 	return TRACE_TYPE_NO_CONSUME;
 }
 
-static enum print_line_t
+static void
 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 		     int type, unsigned long addr, u32 flags)
 {
 	struct fgraph_data *data = iter->private;
 	struct trace_entry *ent = iter->ent;
 	int cpu = iter->cpu;
-	int ret;
 
 	/* Pid */
-	if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
+	verif_pid(s, ent->pid, cpu, data);
 
-	if (type) {
+	if (type)
 		/* Interrupt */
-		ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
-		if (ret == TRACE_TYPE_PARTIAL_LINE)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+		print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 
 	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
-		return 0;
+		return;
 
 	/* Absolute time */
-	if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
-		ret = print_graph_abs_time(iter->ts, s);
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+		print_graph_abs_time(iter->ts, s);
 
 	/* Cpu */
-	if (flags & TRACE_GRAPH_PRINT_CPU) {
-		ret = print_graph_cpu(s, cpu);
-		if (ret == TRACE_TYPE_PARTIAL_LINE)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (flags & TRACE_GRAPH_PRINT_CPU)
+		print_graph_cpu(s, cpu);
 
 	/* Proc */
 	if (flags & TRACE_GRAPH_PRINT_PROC) {
-		ret = print_graph_proc(s, ent->pid);
-		if (ret == TRACE_TYPE_PARTIAL_LINE)
-			return TRACE_TYPE_PARTIAL_LINE;
-
-		ret = trace_seq_puts(s, " | ");
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
+		print_graph_proc(s, ent->pid);
+		trace_seq_puts(s, " | ");
 	}
 
 	/* Latency format */
-	if (trace_flags & TRACE_ITER_LATENCY_FMT) {
-		ret = print_graph_lat_fmt(s, ent);
-		if (ret == TRACE_TYPE_PARTIAL_LINE)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (trace_flags & TRACE_ITER_LATENCY_FMT)
+		print_graph_lat_fmt(s, ent);
 
-	return 0;
+	return;
 }
 
 /*
@@ -1126,8 +998,7 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 	if (check_irq_entry(iter, flags, call->func, call->depth))
 		return TRACE_TYPE_HANDLED;
 
-	if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
 
 	leaf_ret = get_return_for_leaf(iter, field);
 	if (leaf_ret)
@@ -1160,7 +1031,6 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 	pid_t pid = ent->pid;
 	int cpu = iter->cpu;
 	int func_match = 1;
-	int ret;
 	int i;
 
 	if (check_irq_return(iter, flags, trace->depth))
@@ -1186,20 +1056,14 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 		}
 	}
 
-	if (print_graph_prologue(iter, s, 0, 0, flags))
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_prologue(iter, s, 0, 0, flags);
 
 	/* Overhead and duration */
-	ret = print_graph_duration(duration, s, flags);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_duration(duration, s, flags);
 
 	/* Closing brace */
-	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
 
 	/*
 	 * If the return function does not have a matching entry,
@@ -1208,30 +1072,20 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 	 * belongs to, write out the function name. Always do
 	 * that if the funcgraph-tail option is enabled.
 	 */
-	if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) {
-		ret = trace_seq_puts(s, "}\n");
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	} else {
-		ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
+		trace_seq_puts(s, "}\n");
+	else
+		trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
 
 	/* Overrun */
-	if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
-		ret = trace_seq_printf(s, " (Overruns: %lu)\n",
-					trace->overrun);
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (flags & TRACE_GRAPH_PRINT_OVERRUN)
+		trace_seq_printf(s, " (Overruns: %lu)\n",
+				 trace->overrun);
 
-	ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
-			      cpu, pid, flags);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
+			cpu, pid, flags);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -1248,26 +1102,18 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 	if (data)
 		depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
 
-	if (print_graph_prologue(iter, s, 0, 0, flags))
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_prologue(iter, s, 0, 0, flags);
 
 	/* No time */
-	ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
+	print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 
 	/* Indentation */
 	if (depth > 0)
-		for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
-			ret = trace_seq_putc(s, ' ');
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
+			trace_seq_putc(s, ' ');
 
 	/* The comment */
-	ret = trace_seq_puts(s, "/* ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, "/* ");
 
 	switch (iter->ent->type) {
 	case TRACE_BPRINT:
@@ -1296,11 +1142,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 		s->len--;
 	}
 
-	ret = trace_seq_puts(s, " */\n");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, " */\n");
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 
@@ -1407,32 +1251,32 @@ static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
 		print_lat_header(s, flags);
 
 	/* 1st line */
-	seq_printf(s, "#");
+	seq_putc(s, '#');
 	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
-		seq_printf(s, "     TIME       ");
+		seq_puts(s, "     TIME       ");
 	if (flags & TRACE_GRAPH_PRINT_CPU)
-		seq_printf(s, " CPU");
+		seq_puts(s, " CPU");
 	if (flags & TRACE_GRAPH_PRINT_PROC)
-		seq_printf(s, "  TASK/PID       ");
+		seq_puts(s, "  TASK/PID       ");
 	if (lat)
-		seq_printf(s, "||||");
+		seq_puts(s, "||||");
 	if (flags & TRACE_GRAPH_PRINT_DURATION)
-		seq_printf(s, "  DURATION   ");
-	seq_printf(s, "               FUNCTION CALLS\n");
+		seq_puts(s, "  DURATION   ");
+	seq_puts(s, "               FUNCTION CALLS\n");
 
 	/* 2nd line */
-	seq_printf(s, "#");
+	seq_putc(s, '#');
 	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
-		seq_printf(s, "      |         ");
+		seq_puts(s, "      |         ");
 	if (flags & TRACE_GRAPH_PRINT_CPU)
-		seq_printf(s, " |  ");
+		seq_puts(s, " |  ");
 	if (flags & TRACE_GRAPH_PRINT_PROC)
-		seq_printf(s, "   |    |        ");
+		seq_puts(s, "   |    |        ");
 	if (lat)
-		seq_printf(s, "||||");
+		seq_puts(s, "||||");
 	if (flags & TRACE_GRAPH_PRINT_DURATION)
-		seq_printf(s, "   |   |      ");
-	seq_printf(s, "               |   |   |   |\n");
+		seq_puts(s, "   |   |      ");
+	seq_puts(s, "               |   |   |   |\n");
 }
 
 static void print_graph_headers(struct seq_file *s)

kernel/trace/trace_kdb.c

@@ -20,10 +20,12 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file)
 {
 	/* use static because iter can be a bit big for the stack */
 	static struct trace_iterator iter;
+	static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
 	unsigned int old_userobj;
 	int cnt = 0, cpu;
 
 	trace_init_global_iter(&iter);
+	iter.buffer_iter = buffer_iter;
 
 	for_each_tracing_cpu(cpu) {
 		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
@@ -57,19 +59,19 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file)
 		ring_buffer_read_start(iter.buffer_iter[cpu_file]);
 		tracing_iter_reset(&iter, cpu_file);
 	}
-	if (!trace_empty(&iter))
-		trace_find_next_entry_inc(&iter);
-	while (!trace_empty(&iter)) {
+
+	while (trace_find_next_entry_inc(&iter)) {
 		if (!cnt)
 			kdb_printf("---------------------------------\n");
 		cnt++;
 
-		if (trace_find_next_entry_inc(&iter) != NULL && !skip_lines)
+		if (!skip_lines) {
 			print_trace_line(&iter);
-		if (!skip_lines)
 			trace_printk_seq(&iter.seq);
-		else
+		} else {
 			skip_lines--;
+		}
+
 		if (KDB_FLAG(CMD_INTERRUPT))
 			goto out;
 	}
@@ -86,9 +88,12 @@ out:
 		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
 	}
 
-	for_each_tracing_cpu(cpu)
-		if (iter.buffer_iter[cpu])
+	for_each_tracing_cpu(cpu) {
+		if (iter.buffer_iter[cpu]) {
 			ring_buffer_read_finish(iter.buffer_iter[cpu]);
+			iter.buffer_iter[cpu] = NULL;
+		}
+	}
 }
 
 /*

kernel/trace/trace_kprobe.c

@@ -826,7 +826,7 @@ static int probes_seq_show(struct seq_file *m, void *v)
 	struct trace_kprobe *tk = v;
 	int i;
 
-	seq_printf(m, "%c", trace_kprobe_is_return(tk) ? 'r' : 'p');
+	seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 	seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 			ftrace_event_name(&tk->tp.call));
 
@@ -840,7 +840,7 @@ static int probes_seq_show(struct seq_file *m, void *v)
 
 	for (i = 0; i < tk->tp.nr_args; i++)
 		seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
-	seq_printf(m, "\n");
+	seq_putc(m, '\n');
 
 	return 0;
 }
@@ -1024,27 +1024,22 @@ print_kprobe_event(struct trace_iterator *iter, int flags,
 	field = (struct kprobe_trace_entry_head *)iter->ent;
 	tp = container_of(event, struct trace_probe, call.event);
 
-	if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
-		goto partial;
+	trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
 
 	if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
-		goto partial;
+		goto out;
 
-	if (!trace_seq_puts(s, ")"))
-		goto partial;
+	trace_seq_putc(s, ')');
 
 	data = (u8 *)&field[1];
 	for (i = 0; i < tp->nr_args; i++)
 		if (!tp->args[i].type->print(s, tp->args[i].name,
 					     data + tp->args[i].offset, field))
-			goto partial;
+			goto out;
 
-	if (!trace_seq_puts(s, "\n"))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_putc(s, '\n');
+ out:
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -1060,33 +1055,28 @@ print_kretprobe_event(struct trace_iterator *iter, int flags,
 	field = (struct kretprobe_trace_entry_head *)iter->ent;
 	tp = container_of(event, struct trace_probe, call.event);
 
-	if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
-		goto partial;
+	trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
 
 	if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
-		goto partial;
+		goto out;
 
-	if (!trace_seq_puts(s, " <- "))
-		goto partial;
+	trace_seq_puts(s, " <- ");
 
 	if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
-		goto partial;
+		goto out;
 
-	if (!trace_seq_puts(s, ")"))
-		goto partial;
+	trace_seq_putc(s, ')');
 
 	data = (u8 *)&field[1];
 	for (i = 0; i < tp->nr_args; i++)
 		if (!tp->args[i].type->print(s, tp->args[i].name,
 					     data + tp->args[i].offset, field))
-			goto partial;
+			goto out;
 
-	if (!trace_seq_puts(s, "\n"))
-		goto partial;
+	trace_seq_putc(s, '\n');
 
-	return TRACE_TYPE_HANDLED;
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+ out:
+	return trace_handle_return(s);
 }
 
 

kernel/trace/trace_mmiotrace.c

@@ -59,17 +59,15 @@ static void mmio_trace_start(struct trace_array *tr)
 	mmio_reset_data(tr);
 }
 
-static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
+static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
 {
-	int ret = 0;
 	int i;
 	resource_size_t start, end;
 	const struct pci_driver *drv = pci_dev_driver(dev);
 
-	/* XXX: incomplete checks for trace_seq_printf() return value */
-	ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
-				dev->bus->number, dev->devfn,
-				dev->vendor, dev->device, dev->irq);
+	trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
+			 dev->bus->number, dev->devfn,
+			 dev->vendor, dev->device, dev->irq);
 	/*
 	 * XXX: is pci_resource_to_user() appropriate, since we are
 	 * supposed to interpret the __ioremap() phys_addr argument based on
@@ -77,21 +75,20 @@ static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
 	 */
 	for (i = 0; i < 7; i++) {
 		pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
-		ret += trace_seq_printf(s, " %llx",
+		trace_seq_printf(s, " %llx",
 			(unsigned long long)(start |
 			(dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
 	}
 	for (i = 0; i < 7; i++) {
 		pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
-		ret += trace_seq_printf(s, " %llx",
+		trace_seq_printf(s, " %llx",
 			dev->resource[i].start < dev->resource[i].end ?
 			(unsigned long long)(end - start) + 1 : 0);
 	}
 	if (drv)
-		ret += trace_seq_printf(s, " %s\n", drv->name);
+		trace_seq_printf(s, " %s\n", drv->name);
 	else
-		ret += trace_seq_puts(s, " \n");
-	return ret;
+		trace_seq_puts(s, " \n");
 }
 
 static void destroy_header_iter(struct header_iter *hiter)
@@ -179,28 +176,27 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
 	unsigned secs		= (unsigned long)t;
-	int ret = 1;
 
 	trace_assign_type(field, entry);
 	rw = &field->rw;
 
 	switch (rw->opcode) {
 	case MMIO_READ:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 			rw->width, secs, usec_rem, rw->map_id,
 			(unsigned long long)rw->phys,
 			rw->value, rw->pc, 0);
 		break;
 	case MMIO_WRITE:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 			rw->width, secs, usec_rem, rw->map_id,
 			(unsigned long long)rw->phys,
 			rw->value, rw->pc, 0);
 		break;
 	case MMIO_UNKNOWN_OP:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
 			"%02lx 0x%lx %d\n",
 			secs, usec_rem, rw->map_id,
@@ -209,12 +205,11 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 			(rw->value >> 0) & 0xff, rw->pc, 0);
 		break;
 	default:
-		ret = trace_seq_puts(s, "rw what?\n");
+		trace_seq_puts(s, "rw what?\n");
 		break;
 	}
-	if (ret)
-		return TRACE_TYPE_HANDLED;
-	return TRACE_TYPE_PARTIAL_LINE;
+
+	return trace_handle_return(s);
 }
 
 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
@@ -226,31 +221,29 @@ static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
 	unsigned secs		= (unsigned long)t;
-	int ret;
 
 	trace_assign_type(field, entry);
 	m = &field->map;
 
 	switch (m->opcode) {
 	case MMIO_PROBE:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 			secs, usec_rem, m->map_id,
 			(unsigned long long)m->phys, m->virt, m->len,
 			0UL, 0);
 		break;
 	case MMIO_UNPROBE:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"UNMAP %u.%06lu %d 0x%lx %d\n",
 			secs, usec_rem, m->map_id, 0UL, 0);
 		break;
 	default:
-		ret = trace_seq_puts(s, "map what?\n");
+		trace_seq_puts(s, "map what?\n");
 		break;
 	}
-	if (ret)
-		return TRACE_TYPE_HANDLED;
-	return TRACE_TYPE_PARTIAL_LINE;
+
+	return trace_handle_return(s);
 }
 
 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
@@ -262,14 +255,11 @@ static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
 	unsigned secs		= (unsigned long)t;
-	int ret;
 
 	/* The trailing newline must be in the message. */
-	ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t mmio_print_line(struct trace_iterator *iter)

kernel/trace/trace_output.c

@@ -25,15 +25,12 @@ enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *entry = iter->ent;
 	struct bputs_entry *field;
-	int ret;
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_puts(s, field->str);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, field->str);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
@@ -41,15 +38,12 @@ enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *entry = iter->ent;
 	struct bprint_entry *field;
-	int ret;
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_bprintf(s, field->fmt, field->buf);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_bprintf(s, field->fmt, field->buf);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
@@ -57,15 +51,12 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *entry = iter->ent;
 	struct print_entry *field;
-	int ret;
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_puts(s, field->buf);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, field->buf);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 const char *
@@ -124,7 +115,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
 
 	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
 		trace_seq_printf(p, "0x%lx", val);
-		
+
 	trace_seq_putc(p, 0);
 
 	return ret;
@@ -193,7 +184,6 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
 	struct trace_seq *s = &iter->seq;
 	struct trace_seq *p = &iter->tmp_seq;
 	struct trace_entry *entry;
-	int ret;
 
 	event = container_of(trace_event, struct ftrace_event_call, event);
 	entry = iter->ent;
@@ -204,11 +194,9 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
 	}
 
 	trace_seq_init(p);
-	ret = trace_seq_printf(s, "%s: ", ftrace_event_name(event));
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s: ", ftrace_event_name(event));
 
-	return 0;
+	return trace_handle_return(s);
 }
 EXPORT_SYMBOL(ftrace_raw_output_prep);
 
@@ -216,18 +204,11 @@ static int ftrace_output_raw(struct trace_iterator *iter, char *name,
 			     char *fmt, va_list ap)
 {
 	struct trace_seq *s = &iter->seq;
-	int ret;
 
-	ret = trace_seq_printf(s, "%s: ", name);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s: ", name);
+	trace_seq_vprintf(s, fmt, ap);
 
-	ret = trace_seq_vprintf(s, fmt, ap);
-
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 int ftrace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
@@ -260,7 +241,7 @@ static inline const char *kretprobed(const char *name)
 }
 #endif /* CONFIG_KRETPROBES */
 
-static int
+static void
 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
 {
 #ifdef CONFIG_KALLSYMS
@@ -271,12 +252,11 @@ seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
 
 	name = kretprobed(str);
 
-	return trace_seq_printf(s, fmt, name);
+	trace_seq_printf(s, fmt, name);
 #endif
-	return 1;
 }
 
-static int
+static void
 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
 		     unsigned long address)
 {
@@ -287,9 +267,8 @@ seq_print_sym_offset(struct trace_seq *s, const char *fmt,
 	sprint_symbol(str, address);
 	name = kretprobed(str);
 
-	return trace_seq_printf(s, fmt, name);
+	trace_seq_printf(s, fmt, name);
 #endif
-	return 1;
 }
 
 #ifndef CONFIG_64BIT
@@ -320,14 +299,14 @@ int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 		if (file) {
 			ret = trace_seq_path(s, &file->f_path);
 			if (ret)
-				ret = trace_seq_printf(s, "[+0x%lx]",
-						       ip - vmstart);
+				trace_seq_printf(s, "[+0x%lx]",
+						 ip - vmstart);
 		}
 		up_read(&mm->mmap_sem);
 	}
 	if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
-		ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
-	return ret;
+		trace_seq_printf(s, " <" IP_FMT ">", ip);
+	return !trace_seq_has_overflowed(s);
 }
 
 int
@@ -335,7 +314,6 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 		      unsigned long sym_flags)
 {
 	struct mm_struct *mm = NULL;
-	int ret = 1;
 	unsigned int i;
 
 	if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
@@ -354,48 +332,45 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
 		unsigned long ip = entry->caller[i];
 
-		if (ip == ULONG_MAX || !ret)
+		if (ip == ULONG_MAX || trace_seq_has_overflowed(s))
 			break;
-		if (ret)
-			ret = trace_seq_puts(s, " => ");
+
+		trace_seq_puts(s, " => ");
+
 		if (!ip) {
-			if (ret)
-				ret = trace_seq_puts(s, "??");
-			if (ret)
-				ret = trace_seq_putc(s, '\n');
+			trace_seq_puts(s, "??");
+			trace_seq_putc(s, '\n');
 			continue;
 		}
-		if (!ret)
-			break;
-		if (ret)
-			ret = seq_print_user_ip(s, mm, ip, sym_flags);
-		ret = trace_seq_putc(s, '\n');
+
+		seq_print_user_ip(s, mm, ip, sym_flags);
+		trace_seq_putc(s, '\n');
 	}
 
 	if (mm)
 		mmput(mm);
-	return ret;
+
+	return !trace_seq_has_overflowed(s);
 }
 
 int
 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
 {
-	int ret;
-
-	if (!ip)
-		return trace_seq_putc(s, '0');
+	if (!ip) {
+		trace_seq_putc(s, '0');
+		goto out;
+	}
 
 	if (sym_flags & TRACE_ITER_SYM_OFFSET)
-		ret = seq_print_sym_offset(s, "%s", ip);
+		seq_print_sym_offset(s, "%s", ip);
 	else
-		ret = seq_print_sym_short(s, "%s", ip);
-
-	if (!ret)
-		return 0;
+		seq_print_sym_short(s, "%s", ip);
 
 	if (sym_flags & TRACE_ITER_SYM_ADDR)
-		ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
-	return ret;
+		trace_seq_printf(s, " <" IP_FMT ">", ip);
+
+ out:
+	return !trace_seq_has_overflowed(s);
 }
 
 /**
@@ -413,7 +388,6 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 	char irqs_off;
 	int hardirq;
 	int softirq;
-	int ret;
 
 	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
 	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
@@ -445,16 +419,15 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 		softirq ? 's' :
 		'.';
 
-	if (!trace_seq_printf(s, "%c%c%c",
-			      irqs_off, need_resched, hardsoft_irq))
-		return 0;
+	trace_seq_printf(s, "%c%c%c",
+			 irqs_off, need_resched, hardsoft_irq);
 
 	if (entry->preempt_count)
-		ret = trace_seq_printf(s, "%x", entry->preempt_count);
+		trace_seq_printf(s, "%x", entry->preempt_count);
 	else
-		ret = trace_seq_putc(s, '.');
+		trace_seq_putc(s, '.');
 
-	return ret;
+	return !trace_seq_has_overflowed(s);
 }
 
 static int
@@ -464,14 +437,38 @@ lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
 
 	trace_find_cmdline(entry->pid, comm);
 
-	if (!trace_seq_printf(s, "%8.8s-%-5d %3d",
-			      comm, entry->pid, cpu))
-		return 0;
+	trace_seq_printf(s, "%8.8s-%-5d %3d",
+			 comm, entry->pid, cpu);
 
 	return trace_print_lat_fmt(s, entry);
 }
 
-static unsigned long preempt_mark_thresh_us = 100;
+#undef MARK
+#define MARK(v, s) {.val = v, .sym = s}
+/* trace overhead mark */
+static const struct trace_mark {
+	unsigned long long	val; /* unit: nsec */
+	char			sym;
+} mark[] = {
+	MARK(1000000000ULL	, '$'), /* 1 sec */
+	MARK(1000000ULL		, '#'), /* 1000 usecs */
+	MARK(100000ULL		, '!'), /* 100 usecs */
+	MARK(10000ULL		, '+'), /* 10 usecs */
+};
+#undef MARK
+
+char trace_find_mark(unsigned long long d)
+{
+	int i;
+	int size = ARRAY_SIZE(mark);
+
+	for (i = 0; i < size; i++) {
+		if (d >= mark[i].val)
+			break;
+	}
+
+	return (i == size) ? ' ' : mark[i].sym;
+}
 
 static int
 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
@@ -493,24 +490,28 @@ lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
 		unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
 		unsigned long rel_msec = (unsigned long)rel_ts;
 
-		return trace_seq_printf(
-				s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
-				ns2usecs(iter->ts),
-				abs_msec, abs_usec,
-				rel_msec, rel_usec);
+		trace_seq_printf(
+			s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
+			ns2usecs(iter->ts),
+			abs_msec, abs_usec,
+			rel_msec, rel_usec);
+
 	} else if (verbose && !in_ns) {
-		return trace_seq_printf(
-				s, "[%016llx] %lld (+%lld): ",
-				iter->ts, abs_ts, rel_ts);
+		trace_seq_printf(
+			s, "[%016llx] %lld (+%lld): ",
+			iter->ts, abs_ts, rel_ts);
+
 	} else if (!verbose && in_ns) {
-		return trace_seq_printf(
-				s, " %4lldus%c: ",
-				abs_ts,
-				rel_ts > preempt_mark_thresh_us ? '!' :
-				  rel_ts > 1 ? '+' : ' ');
+		trace_seq_printf(
+			s, " %4lldus%c: ",
+			abs_ts,
+			trace_find_mark(rel_ts * NSEC_PER_USEC));
+
 	} else { /* !verbose && !in_ns */
-		return trace_seq_printf(s, " %4lld: ", abs_ts);
+		trace_seq_printf(s, " %4lld: ", abs_ts);
 	}
+
+	return !trace_seq_has_overflowed(s);
 }
 
 int trace_print_context(struct trace_iterator *iter)
@@ -520,34 +521,29 @@ int trace_print_context(struct trace_iterator *iter)
 	unsigned long long t;
 	unsigned long secs, usec_rem;
 	char comm[TASK_COMM_LEN];
-	int ret;
 
 	trace_find_cmdline(entry->pid, comm);
 
-	ret = trace_seq_printf(s, "%16s-%-5d [%03d] ",
+	trace_seq_printf(s, "%16s-%-5d [%03d] ",
 			       comm, entry->pid, iter->cpu);
-	if (!ret)
-		return 0;
 
-	if (trace_flags & TRACE_ITER_IRQ_INFO) {
-		ret = trace_print_lat_fmt(s, entry);
-		if (!ret)
-			return 0;
-	}
+	if (trace_flags & TRACE_ITER_IRQ_INFO)
+		trace_print_lat_fmt(s, entry);
 
 	if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
 		t = ns2usecs(iter->ts);
 		usec_rem = do_div(t, USEC_PER_SEC);
 		secs = (unsigned long)t;
-		return trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
+		trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
 	} else
-		return trace_seq_printf(s, " %12llu: ", iter->ts);
+		trace_seq_printf(s, " %12llu: ", iter->ts);
+
+	return !trace_seq_has_overflowed(s);
 }
 
 int trace_print_lat_context(struct trace_iterator *iter)
 {
 	u64 next_ts;
-	int ret;
 	/* trace_find_next_entry will reset ent_size */
 	int ent_size = iter->ent_size;
 	struct trace_seq *s = &iter->seq;
@@ -567,18 +563,17 @@ int trace_print_lat_context(struct trace_iterator *iter)
 
 		trace_find_cmdline(entry->pid, comm);
 
-		ret = trace_seq_printf(
-				s, "%16s %5d %3d %d %08x %08lx ",
-				comm, entry->pid, iter->cpu, entry->flags,
-				entry->preempt_count, iter->idx);
+		trace_seq_printf(
+			s, "%16s %5d %3d %d %08x %08lx ",
+			comm, entry->pid, iter->cpu, entry->flags,
+			entry->preempt_count, iter->idx);
 	} else {
-		ret = lat_print_generic(s, entry, iter->cpu);
+		lat_print_generic(s, entry, iter->cpu);
 	}
 
-	if (ret)
-		ret = lat_print_timestamp(iter, next_ts);
+	lat_print_timestamp(iter, next_ts);
 
-	return ret;
+	return !trace_seq_has_overflowed(s);
 }
 
 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
@@ -692,7 +687,7 @@ int register_ftrace_event(struct trace_event *event)
 				goto out;
 
 		} else {
-			
+
 			event->type = next_event_type++;
 			list = &ftrace_event_list;
 		}
@@ -764,10 +759,9 @@ EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
 				  struct trace_event *event)
 {
-	if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(&iter->seq);
 }
 
 /* TRACE_FN */
@@ -779,24 +773,16 @@ static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!seq_print_ip_sym(s, field->ip, flags))
-		goto partial;
+	seq_print_ip_sym(s, field->ip, flags);
 
 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
-		if (!trace_seq_puts(s, " <-"))
-			goto partial;
-		if (!seq_print_ip_sym(s,
-				      field->parent_ip,
-				      flags))
-			goto partial;
+		trace_seq_puts(s, " <-");
+		seq_print_ip_sym(s, field->parent_ip, flags);
 	}
-	if (!trace_seq_putc(s, '\n'))
-		goto partial;
 
-	return TRACE_TYPE_HANDLED;
+	trace_seq_putc(s, '\n');
 
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
@@ -806,12 +792,11 @@ static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
-			      field->ip,
-			      field->parent_ip))
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(&iter->seq, "%lx %lx\n",
+			 field->ip,
+			 field->parent_ip);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(&iter->seq);
 }
 
 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
@@ -822,10 +807,10 @@ static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	SEQ_PUT_HEX_FIELD_RET(s, field->ip);
-	SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
+	SEQ_PUT_HEX_FIELD(s, field->ip);
+	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
@@ -836,10 +821,10 @@ static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	SEQ_PUT_FIELD_RET(s, field->ip);
-	SEQ_PUT_FIELD_RET(s, field->parent_ip);
+	SEQ_PUT_FIELD(s, field->ip);
+	SEQ_PUT_FIELD(s, field->parent_ip);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_fn_funcs = {
@@ -868,18 +853,17 @@ static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 	T = task_state_char(field->next_state);
 	S = task_state_char(field->prev_state);
 	trace_find_cmdline(field->next_pid, comm);
-	if (!trace_seq_printf(&iter->seq,
-			      " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
-			      field->prev_pid,
-			      field->prev_prio,
-			      S, delim,
-			      field->next_cpu,
-			      field->next_pid,
-			      field->next_prio,
-			      T, comm))
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(&iter->seq,
+			 " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
+			 field->prev_pid,
+			 field->prev_prio,
+			 S, delim,
+			 field->next_cpu,
+			 field->next_pid,
+			 field->next_prio,
+			 T, comm);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(&iter->seq);
 }
 
 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
@@ -904,17 +888,16 @@ static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 	if (!S)
 		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
-	if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
-			      field->prev_pid,
-			      field->prev_prio,
-			      S,
-			      field->next_cpu,
-			      field->next_pid,
-			      field->next_prio,
-			      T))
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
+			 field->prev_pid,
+			 field->prev_prio,
+			 S,
+			 field->next_cpu,
+			 field->next_pid,
+			 field->next_prio,
+			 T);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(&iter->seq);
 }
 
 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
@@ -942,15 +925,15 @@ static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
 		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
 
-	SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
-	SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
-	SEQ_PUT_HEX_FIELD_RET(s, S);
-	SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
-	SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
-	SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
-	SEQ_PUT_HEX_FIELD_RET(s, T);
+	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
+	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
+	SEQ_PUT_HEX_FIELD(s, S);
+	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
+	SEQ_PUT_HEX_FIELD(s, field->next_pid);
+	SEQ_PUT_HEX_FIELD(s, field->next_prio);
+	SEQ_PUT_HEX_FIELD(s, T);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
@@ -973,14 +956,15 @@ static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	SEQ_PUT_FIELD_RET(s, field->prev_pid);
-	SEQ_PUT_FIELD_RET(s, field->prev_prio);
-	SEQ_PUT_FIELD_RET(s, field->prev_state);
-	SEQ_PUT_FIELD_RET(s, field->next_pid);
-	SEQ_PUT_FIELD_RET(s, field->next_prio);
-	SEQ_PUT_FIELD_RET(s, field->next_state);
+	SEQ_PUT_FIELD(s, field->prev_pid);
+	SEQ_PUT_FIELD(s, field->prev_prio);
+	SEQ_PUT_FIELD(s, field->prev_state);
+	SEQ_PUT_FIELD(s, field->next_cpu);
+	SEQ_PUT_FIELD(s, field->next_pid);
+	SEQ_PUT_FIELD(s, field->next_prio);
+	SEQ_PUT_FIELD(s, field->next_state);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_ctx_funcs = {
@@ -1020,23 +1004,19 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
 	trace_assign_type(field, iter->ent);
 	end = (unsigned long *)((long)iter->ent + iter->ent_size);
 
-	if (!trace_seq_puts(s, "<stack trace>\n"))
-		goto partial;
+	trace_seq_puts(s, "<stack trace>\n");
 
 	for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
-		if (!trace_seq_puts(s, " => "))
-			goto partial;
 
-		if (!seq_print_ip_sym(s, *p, flags))
-			goto partial;
-		if (!trace_seq_putc(s, '\n'))
-			goto partial;
+		if (trace_seq_has_overflowed(s))
+			break;
+
+		trace_seq_puts(s, " => ");
+		seq_print_ip_sym(s, *p, flags);
+		trace_seq_putc(s, '\n');
 	}
 
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_stack_funcs = {
@@ -1057,16 +1037,10 @@ static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_puts(s, "<user stack trace>\n"))
-		goto partial;
+	trace_seq_puts(s, "<user stack trace>\n");
+	seq_print_userip_objs(field, s, flags);
 
-	if (!seq_print_userip_objs(field, s, flags))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_user_stack_funcs = {
@@ -1089,19 +1063,11 @@ trace_bputs_print(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, entry);
 
-	if (!seq_print_ip_sym(s, field->ip, flags))
-		goto partial;
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_puts(s, ": ");
+	trace_seq_puts(s, field->str);
 
-	if (!trace_seq_puts(s, ": "))
-		goto partial;
-
-	if (!trace_seq_puts(s, field->str))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 
@@ -1114,16 +1080,10 @@ trace_bputs_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_printf(s, ": %lx : ", field->ip))
-		goto partial;
+	trace_seq_printf(s, ": %lx : ", field->ip);
+	trace_seq_puts(s, field->str);
 
-	if (!trace_seq_puts(s, field->str))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_bputs_funcs = {
@@ -1147,19 +1107,11 @@ trace_bprint_print(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, entry);
 
-	if (!seq_print_ip_sym(s, field->ip, flags))
-		goto partial;
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_puts(s, ": ");
+	trace_seq_bprintf(s, field->fmt, field->buf);
 
-	if (!trace_seq_puts(s, ": "))
-		goto partial;
-
-	if (!trace_seq_bprintf(s, field->fmt, field->buf))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 
@@ -1172,16 +1124,10 @@ trace_bprint_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_printf(s, ": %lx : ", field->ip))
-		goto partial;
+	trace_seq_printf(s, ": %lx : ", field->ip);
+	trace_seq_bprintf(s, field->fmt, field->buf);
 
-	if (!trace_seq_bprintf(s, field->fmt, field->buf))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_bprint_funcs = {
@@ -1203,16 +1149,10 @@ static enum print_line_t trace_print_print(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!seq_print_ip_sym(s, field->ip, flags))
-		goto partial;
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_printf(s, ": %s", field->buf);
 
-	if (!trace_seq_printf(s, ": %s", field->buf))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
@@ -1222,13 +1162,9 @@ static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
-		goto partial;
+	trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
 
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(&iter->seq);
 }
 
 static struct trace_event_functions trace_print_funcs = {

kernel/trace/trace_output.h

@@ -35,17 +35,11 @@ trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry);
 extern int __unregister_ftrace_event(struct trace_event *event);
 extern struct rw_semaphore trace_event_sem;
 
-#define SEQ_PUT_FIELD_RET(s, x)				\
-do {							\
-	if (!trace_seq_putmem(s, &(x), sizeof(x)))	\
-		return TRACE_TYPE_PARTIAL_LINE;		\
-} while (0)
+#define SEQ_PUT_FIELD(s, x)				\
+	trace_seq_putmem(s, &(x), sizeof(x))
 
-#define SEQ_PUT_HEX_FIELD_RET(s, x)			\
-do {							\
-	if (!trace_seq_putmem_hex(s, &(x), sizeof(x)))	\
-		return TRACE_TYPE_PARTIAL_LINE;		\
-} while (0)
+#define SEQ_PUT_HEX_FIELD(s, x)				\
+	trace_seq_putmem_hex(s, &(x), sizeof(x))
 
 #endif
 

kernel/trace/trace_printk.c

@@ -305,7 +305,7 @@ static int t_show(struct seq_file *m, void *v)
 			seq_puts(m, "\\t");
 			break;
 		case '\\':
-			seq_puts(m, "\\");
+			seq_putc(m, '\\');
 			break;
 		case '"':
 			seq_puts(m, "\\\"");

kernel/trace/trace_probe.c

@@ -40,7 +40,8 @@ const char *reserved_field_names[] = {
 int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,	\
 				void *data, void *ent)			\
 {									\
-	return trace_seq_printf(s, " %s=" fmt, name, *(type *)data);	\
+	trace_seq_printf(s, " %s=" fmt, name, *(type *)data);		\
+	return !trace_seq_has_overflowed(s);				\
 }									\
 const char PRINT_TYPE_FMT_NAME(type)[] = fmt;				\
 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
@@ -61,10 +62,11 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
 	int len = *(u32 *)data >> 16;
 
 	if (!len)
-		return trace_seq_printf(s, " %s=(fault)", name);
+		trace_seq_printf(s, " %s=(fault)", name);
 	else
-		return trace_seq_printf(s, " %s=\"%s\"", name,
-					(const char *)get_loc_data(data, ent));
+		trace_seq_printf(s, " %s=\"%s\"", name,
+				 (const char *)get_loc_data(data, ent));
+	return !trace_seq_has_overflowed(s);
 }
 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
 

kernel/trace/trace_sched_switch.c

@@ -14,122 +14,26 @@
 
 #include "trace.h"
 
-static struct trace_array	*ctx_trace;
-static int __read_mostly	tracer_enabled;
 static int			sched_ref;
 static DEFINE_MUTEX(sched_register_mutex);
-static int			sched_stopped;
-
-
-void
-tracing_sched_switch_trace(struct trace_array *tr,
-			   struct task_struct *prev,
-			   struct task_struct *next,
-			   unsigned long flags, int pc)
-{
-	struct ftrace_event_call *call = &event_context_switch;
-	struct ring_buffer *buffer = tr->trace_buffer.buffer;
-	struct ring_buffer_event *event;
-	struct ctx_switch_entry *entry;
-
-	event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
-					  sizeof(*entry), flags, pc);
-	if (!event)
-		return;
-	entry	= ring_buffer_event_data(event);
-	entry->prev_pid			= prev->pid;
-	entry->prev_prio		= prev->prio;
-	entry->prev_state		= prev->state;
-	entry->next_pid			= next->pid;
-	entry->next_prio		= next->prio;
-	entry->next_state		= next->state;
-	entry->next_cpu	= task_cpu(next);
-
-	if (!call_filter_check_discard(call, entry, buffer, event))
-		trace_buffer_unlock_commit(buffer, event, flags, pc);
-}
 
 static void
 probe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next)
 {
-	struct trace_array_cpu *data;
-	unsigned long flags;
-	int cpu;
-	int pc;
-
 	if (unlikely(!sched_ref))
 		return;
 
 	tracing_record_cmdline(prev);
 	tracing_record_cmdline(next);
-
-	if (!tracer_enabled || sched_stopped)
-		return;
-
-	pc = preempt_count();
-	local_irq_save(flags);
-	cpu = raw_smp_processor_id();
-	data = per_cpu_ptr(ctx_trace->trace_buffer.data, cpu);
-
-	if (likely(!atomic_read(&data->disabled)))
-		tracing_sched_switch_trace(ctx_trace, prev, next, flags, pc);
-
-	local_irq_restore(flags);
-}
-
-void
-tracing_sched_wakeup_trace(struct trace_array *tr,
-			   struct task_struct *wakee,
-			   struct task_struct *curr,
-			   unsigned long flags, int pc)
-{
-	struct ftrace_event_call *call = &event_wakeup;
-	struct ring_buffer_event *event;
-	struct ctx_switch_entry *entry;
-	struct ring_buffer *buffer = tr->trace_buffer.buffer;
-
-	event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
-					  sizeof(*entry), flags, pc);
-	if (!event)
-		return;
-	entry	= ring_buffer_event_data(event);
-	entry->prev_pid			= curr->pid;
-	entry->prev_prio		= curr->prio;
-	entry->prev_state		= curr->state;
-	entry->next_pid			= wakee->pid;
-	entry->next_prio		= wakee->prio;
-	entry->next_state		= wakee->state;
-	entry->next_cpu			= task_cpu(wakee);
-
-	if (!call_filter_check_discard(call, entry, buffer, event))
-		trace_buffer_unlock_commit(buffer, event, flags, pc);
 }
 
 static void
 probe_sched_wakeup(void *ignore, struct task_struct *wakee, int success)
 {
-	struct trace_array_cpu *data;
-	unsigned long flags;
-	int cpu, pc;
-
 	if (unlikely(!sched_ref))
 		return;
 
 	tracing_record_cmdline(current);
-
-	if (!tracer_enabled || sched_stopped)
-		return;
-
-	pc = preempt_count();
-	local_irq_save(flags);
-	cpu = raw_smp_processor_id();
-	data = per_cpu_ptr(ctx_trace->trace_buffer.data, cpu);
-
-	if (likely(!atomic_read(&data->disabled)))
-		tracing_sched_wakeup_trace(ctx_trace, wakee, current,
-					   flags, pc);
-
-	local_irq_restore(flags);
 }
 
 static int tracing_sched_register(void)
@@ -197,51 +101,3 @@ void tracing_stop_cmdline_record(void)
 {
 	tracing_stop_sched_switch();
 }
-
-/**
- * tracing_start_sched_switch_record - start tracing context switches
- *
- * Turns on context switch tracing for a tracer.
- */
-void tracing_start_sched_switch_record(void)
-{
-	if (unlikely(!ctx_trace)) {
-		WARN_ON(1);
-		return;
-	}
-
-	tracing_start_sched_switch();
-
-	mutex_lock(&sched_register_mutex);
-	tracer_enabled++;
-	mutex_unlock(&sched_register_mutex);
-}
-
-/**
- * tracing_stop_sched_switch_record - start tracing context switches
- *
- * Turns off context switch tracing for a tracer.
- */
-void tracing_stop_sched_switch_record(void)
-{
-	mutex_lock(&sched_register_mutex);
-	tracer_enabled--;
-	WARN_ON(tracer_enabled < 0);
-	mutex_unlock(&sched_register_mutex);
-
-	tracing_stop_sched_switch();
-}
-
-/**
- * tracing_sched_switch_assign_trace - assign a trace array for ctx switch
- * @tr: trace array pointer to assign
- *
- * Some tracers might want to record the context switches in their
- * trace. This function lets those tracers assign the trace array
- * to use.
- */
-void tracing_sched_switch_assign_trace(struct trace_array *tr)
-{
-	ctx_trace = tr;
-}
-

kernel/trace/trace_sched_wakeup.c

@@ -365,6 +365,62 @@ probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
 	wakeup_current_cpu = cpu;
 }
 
+static void
+tracing_sched_switch_trace(struct trace_array *tr,
+			   struct task_struct *prev,
+			   struct task_struct *next,
+			   unsigned long flags, int pc)
+{
+	struct ftrace_event_call *call = &event_context_switch;
+	struct ring_buffer *buffer = tr->trace_buffer.buffer;
+	struct ring_buffer_event *event;
+	struct ctx_switch_entry *entry;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
+					  sizeof(*entry), flags, pc);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->prev_pid			= prev->pid;
+	entry->prev_prio		= prev->prio;
+	entry->prev_state		= prev->state;
+	entry->next_pid			= next->pid;
+	entry->next_prio		= next->prio;
+	entry->next_state		= next->state;
+	entry->next_cpu	= task_cpu(next);
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit(buffer, event, flags, pc);
+}
+
+static void
+tracing_sched_wakeup_trace(struct trace_array *tr,
+			   struct task_struct *wakee,
+			   struct task_struct *curr,
+			   unsigned long flags, int pc)
+{
+	struct ftrace_event_call *call = &event_wakeup;
+	struct ring_buffer_event *event;
+	struct ctx_switch_entry *entry;
+	struct ring_buffer *buffer = tr->trace_buffer.buffer;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
+					  sizeof(*entry), flags, pc);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->prev_pid			= curr->pid;
+	entry->prev_prio		= curr->prio;
+	entry->prev_state		= curr->state;
+	entry->next_pid			= wakee->pid;
+	entry->next_prio		= wakee->prio;
+	entry->next_state		= wakee->state;
+	entry->next_cpu			= task_cpu(wakee);
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit(buffer, event, flags, pc);
+}
+
 static void notrace
 probe_wakeup_sched_switch(void *ignore,
 			  struct task_struct *prev, struct task_struct *next)

kernel/trace/trace_seq.c

@@ -69,20 +69,15 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
  * trace_seq_printf() is used to store strings into a special
  * buffer (@s). Then the output may be either used by
  * the sequencer or pulled into another buffer.
- *
- * Returns 1 if we successfully written all the contents to
- *   the buffer.
-  * Returns 0 if we the length to write is bigger than the
- *   reserved buffer space. In this case, nothing gets written.
  */
-int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 {
 	unsigned int len = TRACE_SEQ_BUF_LEFT(s);
 	va_list ap;
 	int ret;
 
 	if (s->full || !len)
-		return 0;
+		return;
 
 	va_start(ap, fmt);
 	ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
@@ -91,12 +86,10 @@ int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 	/* If we can't write it all, don't bother writing anything */
 	if (ret >= len) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	s->len += ret;
-
-	return 1;
 }
 EXPORT_SYMBOL_GPL(trace_seq_printf);
 
@@ -107,25 +100,18 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
  * @nmaskbits:	The number of bits that are valid in @maskp
  *
  * Writes a ASCII representation of a bitmask string into @s.
- *
- * Returns 1 if we successfully written all the contents to
- *   the buffer.
- * Returns 0 if we the length to write is bigger than the
- *   reserved buffer space. In this case, nothing gets written.
  */
-int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
 		      int nmaskbits)
 {
 	unsigned int len = TRACE_SEQ_BUF_LEFT(s);
 	int ret;
 
 	if (s->full || !len)
-		return 0;
+		return;
 
-	ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
+	ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
 	s->len += ret;
-
-	return 1;
 }
 EXPORT_SYMBOL_GPL(trace_seq_bitmask);
 
@@ -139,28 +125,24 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
  * trace_seq_printf is used to store strings into a special
  * buffer (@s). Then the output may be either used by
  * the sequencer or pulled into another buffer.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
 {
 	unsigned int len = TRACE_SEQ_BUF_LEFT(s);
 	int ret;
 
 	if (s->full || !len)
-		return 0;
+		return;
 
 	ret = vsnprintf(s->buffer + s->len, len, fmt, args);
 
 	/* If we can't write it all, don't bother writing anything */
 	if (ret >= len) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	s->len += ret;
-
-	return len;
 }
 EXPORT_SYMBOL_GPL(trace_seq_vprintf);
 
@@ -178,28 +160,24 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf);
  *
  * This function will take the format and the binary array and finish
  * the conversion into the ASCII string within the buffer.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
 	unsigned int len = TRACE_SEQ_BUF_LEFT(s);
 	int ret;
 
 	if (s->full || !len)
-		return 0;
+		return;
 
 	ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
 
 	/* If we can't write it all, don't bother writing anything */
 	if (ret >= len) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	s->len += ret;
-
-	return len;
 }
 EXPORT_SYMBOL_GPL(trace_seq_bprintf);
 
@@ -212,25 +190,21 @@ EXPORT_SYMBOL_GPL(trace_seq_bprintf);
  * copy to user routines. This function records a simple string
  * into a special buffer (@s) for later retrieval by a sequencer
  * or other mechanism.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_puts(struct trace_seq *s, const char *str)
+void trace_seq_puts(struct trace_seq *s, const char *str)
 {
 	unsigned int len = strlen(str);
 
 	if (s->full)
-		return 0;
+		return;
 
 	if (len > TRACE_SEQ_BUF_LEFT(s)) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	memcpy(s->buffer + s->len, str, len);
 	s->len += len;
-
-	return len;
 }
 EXPORT_SYMBOL_GPL(trace_seq_puts);
 
@@ -243,22 +217,18 @@ EXPORT_SYMBOL_GPL(trace_seq_puts);
  * copy to user routines. This function records a simple charater
  * into a special buffer (@s) for later retrieval by a sequencer
  * or other mechanism.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_putc(struct trace_seq *s, unsigned char c)
+void trace_seq_putc(struct trace_seq *s, unsigned char c)
 {
 	if (s->full)
-		return 0;
+		return;
 
 	if (TRACE_SEQ_BUF_LEFT(s) < 1) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	s->buffer[s->len++] = c;
-
-	return 1;
 }
 EXPORT_SYMBOL_GPL(trace_seq_putc);
 
@@ -271,23 +241,19 @@ EXPORT_SYMBOL_GPL(trace_seq_putc);
  * There may be cases where raw memory needs to be written into the
  * buffer and a strcpy() would not work. Using this function allows
  * for such cases.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
+void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
 {
 	if (s->full)
-		return 0;
+		return;
 
 	if (len > TRACE_SEQ_BUF_LEFT(s)) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	memcpy(s->buffer + s->len, mem, len);
 	s->len += len;
-
-	return len;
 }
 EXPORT_SYMBOL_GPL(trace_seq_putmem);
 
@@ -303,20 +269,17 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
  * This is similar to trace_seq_putmem() except instead of just copying the
  * raw memory into the buffer it writes its ASCII representation of it
  * in hex characters.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 			 unsigned int len)
 {
 	unsigned char hex[HEX_CHARS];
 	const unsigned char *data = mem;
 	unsigned int start_len;
 	int i, j;
-	int cnt = 0;
 
 	if (s->full)
-		return 0;
+		return;
 
 	while (len) {
 		start_len = min(len, HEX_CHARS - 1);
@@ -335,9 +298,8 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 		len -= j / 2;
 		hex[j++] = ' ';
 
-		cnt += trace_seq_putmem(s, hex, j);
+		trace_seq_putmem(s, hex, j);
 	}
-	return cnt;
 }
 EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
 

kernel/trace/trace_syscalls.c

@@ -114,7 +114,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
 	struct trace_entry *ent = iter->ent;
 	struct syscall_trace_enter *trace;
 	struct syscall_metadata *entry;
-	int i, ret, syscall;
+	int i, syscall;
 
 	trace = (typeof(trace))ent;
 	syscall = trace->nr;
@@ -128,35 +128,28 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
 		goto end;
 	}
 
-	ret = trace_seq_printf(s, "%s(", entry->name);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s(", entry->name);
 
 	for (i = 0; i < entry->nb_args; i++) {
+
+		if (trace_seq_has_overflowed(s))
+			goto end;
+
 		/* parameter types */
-		if (trace_flags & TRACE_ITER_VERBOSE) {
-			ret = trace_seq_printf(s, "%s ", entry->types[i]);
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		if (trace_flags & TRACE_ITER_VERBOSE)
+			trace_seq_printf(s, "%s ", entry->types[i]);
+
 		/* parameter values */
-		ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
-				       trace->args[i],
-				       i == entry->nb_args - 1 ? "" : ", ");
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+				 trace->args[i],
+				 i == entry->nb_args - 1 ? "" : ", ");
 	}
 
-	ret = trace_seq_putc(s, ')');
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
+	trace_seq_putc(s, ')');
 end:
-	ret =  trace_seq_putc(s, '\n');
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_putc(s, '\n');
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -168,7 +161,6 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 	struct syscall_trace_exit *trace;
 	int syscall;
 	struct syscall_metadata *entry;
-	int ret;
 
 	trace = (typeof(trace))ent;
 	syscall = trace->nr;
@@ -176,7 +168,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 
 	if (!entry) {
 		trace_seq_putc(s, '\n');
-		return TRACE_TYPE_HANDLED;
+		goto out;
 	}
 
 	if (entry->exit_event->event.type != ent->type) {
@@ -184,12 +176,11 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 		return TRACE_TYPE_UNHANDLED;
 	}
 
-	ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+	trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
 				trace->ret);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
 
-	return TRACE_TYPE_HANDLED;
+ out:
+	return trace_handle_return(s);
 }
 
 extern char *__bad_type_size(void);

kernel/trace/trace_uprobe.c

@@ -552,8 +552,7 @@ error:
 	return ret;
 
 fail_address_parse:
-	if (inode)
-		iput(inode);
+	iput(inode);
 
 	pr_info("Failed to parse address or file.\n");
 
@@ -606,7 +605,7 @@ static int probes_seq_show(struct seq_file *m, void *v)
 	for (i = 0; i < tu->tp.nr_args; i++)
 		seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
 
-	seq_printf(m, "\n");
+	seq_putc(m, '\n');
 	return 0;
 }
 
@@ -852,16 +851,14 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
 	tu = container_of(event, struct trace_uprobe, tp.call.event);
 
 	if (is_ret_probe(tu)) {
-		if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
-					ftrace_event_name(&tu->tp.call),
-					entry->vaddr[1], entry->vaddr[0]))
-			goto partial;
+		trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
+				 ftrace_event_name(&tu->tp.call),
+				 entry->vaddr[1], entry->vaddr[0]);
 		data = DATAOF_TRACE_ENTRY(entry, true);
 	} else {
-		if (!trace_seq_printf(s, "%s: (0x%lx)",
-					ftrace_event_name(&tu->tp.call),
-					entry->vaddr[0]))
-			goto partial;
+		trace_seq_printf(s, "%s: (0x%lx)",
+				 ftrace_event_name(&tu->tp.call),
+				 entry->vaddr[0]);
 		data = DATAOF_TRACE_ENTRY(entry, false);
 	}
 
@@ -869,14 +866,13 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
 		struct probe_arg *parg = &tu->tp.args[i];
 
 		if (!parg->type->print(s, parg->name, data + parg->offset, entry))
-			goto partial;
+			goto out;
 	}
 
-	if (trace_seq_puts(s, "\n"))
-		return TRACE_TYPE_HANDLED;
+	trace_seq_putc(s, '\n');
 
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+ out:
+	return trace_handle_return(s);
 }
 
 typedef bool (*filter_func_t)(struct uprobe_consumer *self,