tracing: let trace_signal_generate() report more info, kill overflow_fail/lose_info

__send_signal()->trace_signal_generate() doesn't report enough info.
The users want to know was the signal actually delivered or not, and
they also need the shared/private info.

The patch moves trace_signal_generate() at the end of __send_signal()
and adds the 2 additional arguments.

This also allows us to kill trace_signal_overflow_fail/lose_info, we
can simply add the appropriate TRACE_SIGNAL_ "result" codes.

Reported-by: Seiji Aguchi <saguchi@redhat.com>
Reviewed-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

include/trace/events/signal.h

@@ -23,11 +23,23 @@
 		}						\
 	} while (0)
 
+#ifndef TRACE_HEADER_MULTI_READ
+enum {
+	TRACE_SIGNAL_DELIVERED,
+	TRACE_SIGNAL_IGNORED,
+	TRACE_SIGNAL_ALREADY_PENDING,
+	TRACE_SIGNAL_OVERFLOW_FAIL,
+	TRACE_SIGNAL_LOSE_INFO,
+};
+#endif
+
 /**
  * signal_generate - called when a signal is generated
  * @sig: signal number
  * @info: pointer to struct siginfo
  * @task: pointer to struct task_struct
+ * @group: shared or private
+ * @result: TRACE_SIGNAL_*
  *
  * Current process sends a 'sig' signal to 'task' process with
  * 'info' siginfo. If 'info' is SEND_SIG_NOINFO or SEND_SIG_PRIV,
@@ -37,9 +49,10 @@
  */
 TRACE_EVENT(signal_generate,
 
-	TP_PROTO(int sig, struct siginfo *info, struct task_struct *task),
+	TP_PROTO(int sig, struct siginfo *info, struct task_struct *task,
+			int group, int result),
 
-	TP_ARGS(sig, info, task),
+	TP_ARGS(sig, info, task, group, result),
 
 	TP_STRUCT__entry(
 		__field(	int,	sig			)
@@ -47,6 +60,8 @@ TRACE_EVENT(signal_generate,
 		__field(	int,	code			)
 		__array(	char,	comm,	TASK_COMM_LEN	)
 		__field(	pid_t,	pid			)
+		__field(	int,	group			)
+		__field(	int,	result			)
 	),
 
 	TP_fast_assign(
@@ -54,11 +69,14 @@ TRACE_EVENT(signal_generate,
 		TP_STORE_SIGINFO(__entry, info);
 		memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
 		__entry->pid	= task->pid;
+		__entry->group	= group;
+		__entry->result	= result;
 	),
 
-	TP_printk("sig=%d errno=%d code=%d comm=%s pid=%d",
+	TP_printk("sig=%d errno=%d code=%d comm=%s pid=%d grp=%d res=%d",
 		  __entry->sig, __entry->errno, __entry->code,
-		  __entry->comm, __entry->pid)
+		  __entry->comm, __entry->pid, __entry->group,
+		  __entry->result)
 );
 
 /**
@@ -101,65 +119,6 @@ TRACE_EVENT(signal_deliver,
 		  __entry->sa_handler, __entry->sa_flags)
 );
 
-DECLARE_EVENT_CLASS(signal_queue_overflow,
-
-	TP_PROTO(int sig, int group, struct siginfo *info),
-
-	TP_ARGS(sig, group, info),
-
-	TP_STRUCT__entry(
-		__field(	int,	sig	)
-		__field(	int,	group	)
-		__field(	int,	errno	)
-		__field(	int,	code	)
-	),
-
-	TP_fast_assign(
-		__entry->sig	= sig;
-		__entry->group	= group;
-		TP_STORE_SIGINFO(__entry, info);
-	),
-
-	TP_printk("sig=%d group=%d errno=%d code=%d",
-		  __entry->sig, __entry->group, __entry->errno, __entry->code)
-);
-
-/**
- * signal_overflow_fail - called when signal queue is overflow
- * @sig: signal number
- * @group: signal to process group or not (bool)
- * @info: pointer to struct siginfo
- *
- * Kernel fails to generate 'sig' signal with 'info' siginfo, because
- * siginfo queue is overflow, and the signal is dropped.
- * 'group' is not 0 if the signal will be sent to a process group.
- * 'sig' is always one of RT signals.
- */
-DEFINE_EVENT(signal_queue_overflow, signal_overflow_fail,
-
-	TP_PROTO(int sig, int group, struct siginfo *info),
-
-	TP_ARGS(sig, group, info)
-);
-
-/**
- * signal_lose_info - called when siginfo is lost
- * @sig: signal number
- * @group: signal to process group or not (bool)
- * @info: pointer to struct siginfo
- *
- * Kernel generates 'sig' signal but loses 'info' siginfo, because siginfo
- * queue is overflow.
- * 'group' is not 0 if the signal will be sent to a process group.
- * 'sig' is always one of non-RT signals.
- */
-DEFINE_EVENT(signal_queue_overflow, signal_lose_info,
-
-	TP_PROTO(int sig, int group, struct siginfo *info),
-
-	TP_ARGS(sig, group, info)
-);
-
 #endif /* _TRACE_SIGNAL_H */
 
 /* This part must be outside protection */