Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - procfs updates

 - various misc bits

 - lib/ updates

 - epoll updates

 - autofs

 - fatfs

 - a few more MM bits

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (58 commits)
  mm/page_io.c: fix polled swap page in
  checkpatch: add Co-developed-by to signature tags
  docs: fix Co-Developed-by docs
  drivers/base/platform.c: kmemleak ignore a known leak
  fs: don't open code lru_to_page()
  fs/: remove caller signal_pending branch predictions
  mm/: remove caller signal_pending branch predictions
  arch/arc/mm/fault.c: remove caller signal_pending_branch predictions
  kernel/sched/: remove caller signal_pending branch predictions
  kernel/locking/mutex.c: remove caller signal_pending branch predictions
  mm: select HAVE_MOVE_PMD on x86 for faster mremap
  mm: speed up mremap by 20x on large regions
  mm: treewide: remove unused address argument from pte_alloc functions
  initramfs: cleanup incomplete rootfs
  scripts/gdb: fix lx-version string output
  kernel/kcov.c: mark write_comp_data() as notrace
  kernel/sysctl: add panic_print into sysctl
  panic: add options to print system info when panic happens
  bfs: extra sanity checking and static inode bitmap
  exec: separate MM_ANONPAGES and RLIMIT_STACK accounting
  ...

kernel/fork.c

@@ -164,10 +164,6 @@ static inline void free_task_struct(struct task_struct *tsk)
 }
 #endif
 
-void __weak arch_release_thread_stack(unsigned long *stack)
-{
-}
-
 #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
 
 /*
@@ -422,7 +418,6 @@ static void release_task_stack(struct task_struct *tsk)
 		return;  /* Better to leak the stack than to free prematurely */
 
 	account_kernel_stack(tsk, -1);
-	arch_release_thread_stack(tsk->stack);
 	free_thread_stack(tsk);
 	tsk->stack = NULL;
 #ifdef CONFIG_VMAP_STACK

kernel/hung_task.c

@@ -34,7 +34,7 @@ int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
  * is disabled during the critical section. It also controls the size of
  * the RCU grace period. So it needs to be upper-bound.
  */
-#define HUNG_TASK_BATCHING 1024
+#define HUNG_TASK_LOCK_BREAK (HZ / 10)
 
 /*
  * Zero means infinite timeout - no checking done:
@@ -112,8 +112,11 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 
 	trace_sched_process_hang(t);
 
-	if (!sysctl_hung_task_warnings && !sysctl_hung_task_panic)
-		return;
+	if (sysctl_hung_task_panic) {
+		console_verbose();
+		hung_task_show_lock = true;
+		hung_task_call_panic = true;
+	}
 
 	/*
 	 * Ok, the task did not get scheduled for more than 2 minutes,
@@ -135,11 +138,6 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 	}
 
 	touch_nmi_watchdog();
-
-	if (sysctl_hung_task_panic) {
-		hung_task_show_lock = true;
-		hung_task_call_panic = true;
-	}
 }
 
 /*
@@ -173,7 +171,7 @@ static bool rcu_lock_break(struct task_struct *g, struct task_struct *t)
 static void check_hung_uninterruptible_tasks(unsigned long timeout)
 {
 	int max_count = sysctl_hung_task_check_count;
-	int batch_count = HUNG_TASK_BATCHING;
+	unsigned long last_break = jiffies;
 	struct task_struct *g, *t;
 
 	/*
@@ -188,10 +186,10 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
 	for_each_process_thread(g, t) {
 		if (!max_count--)
 			goto unlock;
-		if (!--batch_count) {
-			batch_count = HUNG_TASK_BATCHING;
+		if (time_after(jiffies, last_break + HUNG_TASK_LOCK_BREAK)) {
 			if (!rcu_lock_break(g, t))
 				goto unlock;
+			last_break = jiffies;
 		}
 		/* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
 		if (t->state == TASK_UNINTERRUPTIBLE)

kernel/kcov.c

@@ -112,7 +112,7 @@ void notrace __sanitizer_cov_trace_pc(void)
 EXPORT_SYMBOL(__sanitizer_cov_trace_pc);
 
 #ifdef CONFIG_KCOV_ENABLE_COMPARISONS
-static void write_comp_data(u64 type, u64 arg1, u64 arg2, u64 ip)
+static void notrace write_comp_data(u64 type, u64 arg1, u64 arg2, u64 ip)
 {
 	struct task_struct *t;
 	u64 *area;

kernel/locking/mutex.c

@@ -987,7 +987,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 		 * wait_lock. This ensures the lock cancellation is ordered
 		 * against mutex_unlock() and wake-ups do not go missing.
 		 */
-		if (unlikely(signal_pending_state(state, current))) {
+		if (signal_pending_state(state, current)) {
 			ret = -EINTR;
 			goto err;
 		}

kernel/panic.c

@@ -46,6 +46,13 @@ int panic_on_warn __read_mostly;
 int panic_timeout = CONFIG_PANIC_TIMEOUT;
 EXPORT_SYMBOL_GPL(panic_timeout);
 
+#define PANIC_PRINT_TASK_INFO		0x00000001
+#define PANIC_PRINT_MEM_INFO		0x00000002
+#define PANIC_PRINT_TIMER_INFO		0x00000004
+#define PANIC_PRINT_LOCK_INFO		0x00000008
+#define PANIC_PRINT_FTRACE_INFO		0x00000010
+unsigned long panic_print;
+
 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
 
 EXPORT_SYMBOL(panic_notifier_list);
@@ -125,6 +132,24 @@ void nmi_panic(struct pt_regs *regs, const char *msg)
 }
 EXPORT_SYMBOL(nmi_panic);
 
+static void panic_print_sys_info(void)
+{
+	if (panic_print & PANIC_PRINT_TASK_INFO)
+		show_state();
+
+	if (panic_print & PANIC_PRINT_MEM_INFO)
+		show_mem(0, NULL);
+
+	if (panic_print & PANIC_PRINT_TIMER_INFO)
+		sysrq_timer_list_show();
+
+	if (panic_print & PANIC_PRINT_LOCK_INFO)
+		debug_show_all_locks();
+
+	if (panic_print & PANIC_PRINT_FTRACE_INFO)
+		ftrace_dump(DUMP_ALL);
+}
+
 /**
  *	panic - halt the system
  *	@fmt: The text string to print
@@ -254,6 +279,8 @@ void panic(const char *fmt, ...)
 	debug_locks_off();
 	console_flush_on_panic();
 
+	panic_print_sys_info();
+
 	if (!panic_blink)
 		panic_blink = no_blink;
 
@@ -658,6 +685,7 @@ void refcount_error_report(struct pt_regs *regs, const char *err)
 #endif
 
 core_param(panic, panic_timeout, int, 0644);
+core_param(panic_print, panic_print, ulong, 0644);
 core_param(pause_on_oops, pause_on_oops, int, 0644);
 core_param(panic_on_warn, panic_on_warn, int, 0644);
 core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);

kernel/sched/core.c

@@ -3416,7 +3416,7 @@ static void __sched notrace __schedule(bool preempt)
 
 	switch_count = &prev->nivcsw;
 	if (!preempt && prev->state) {
-		if (unlikely(signal_pending_state(prev->state, prev))) {
+		if (signal_pending_state(prev->state, prev)) {
 			prev->state = TASK_RUNNING;
 		} else {
 			deactivate_task(rq, prev, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);

kernel/sched/swait.c

@@ -93,7 +93,7 @@ long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait
 	long ret = 0;
 
 	raw_spin_lock_irqsave(&q->lock, flags);
-	if (unlikely(signal_pending_state(state, current))) {
+	if (signal_pending_state(state, current)) {
 		/*
 		 * See prepare_to_wait_event(). TL;DR, subsequent swake_up_one()
 		 * must not see us.

kernel/sched/wait.c

@@ -264,7 +264,7 @@ long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_en
 	long ret = 0;
 
 	spin_lock_irqsave(&wq_head->lock, flags);
-	if (unlikely(signal_pending_state(state, current))) {
+	if (signal_pending_state(state, current)) {
 		/*
 		 * Exclusive waiter must not fail if it was selected by wakeup,
 		 * it should "consume" the condition we were waiting for.

kernel/sysctl.c

@@ -807,6 +807,13 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+	{
+		.procname	= "panic_print",
+		.data		= &panic_print,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+	},
 #if defined CONFIG_PRINTK
 	{
 		.procname	= "printk",
@@ -2787,6 +2794,8 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int
 			bool neg;
 
 			left -= proc_skip_spaces(&p);
+			if (!left)
+				break;
 
 			err = proc_get_long(&p, &left, &val, &neg,
 					     proc_wspace_sep,

kernel/sysctl_binary.c

@@ -140,6 +140,7 @@ static const struct bin_table bin_kern_table[] = {
 	{ CTL_INT,	KERN_MAX_LOCK_DEPTH,		"max_lock_depth" },
 	{ CTL_INT,	KERN_PANIC_ON_NMI,		"panic_on_unrecovered_nmi" },
 	{ CTL_INT,	KERN_PANIC_ON_WARN,		"panic_on_warn" },
+	{ CTL_ULONG,	KERN_PANIC_PRINT,		"panic_print" },
 	{}
 };