[PATCH -tip 2/3] tracepoint: Add signal deliver event

[Masami Hiramatsu]

Add a tracepoint where a process gets a signal. This tracepoint
shows signal-number, sa-handler and sa-flag.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
---

 include/trace/events/signal.h |   24 ++++++++++++++++++++++++
 kernel/signal.c               |    3 +++
 2 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/include/trace/events/signal.h b/include/trace/events/signal.h
index c7817f3..6dfd88d 100644
--- a/include/trace/events/signal.h
+++ b/include/trace/events/signal.h
@@ -32,6 +32,30 @@ TRACE_EVENT(signal_generate,
 		  __entry->sig, __entry->comm, __entry->pid)
 );
 
+/*
+ * Tracepoint for delivering a signal:
+ */
+TRACE_EVENT(signal_deliver,
+
+	TP_PROTO(int sig, struct k_sigaction *ka),
+
+	TP_ARGS(sig, ka),
+
+	TP_STRUCT__entry(
+		__field(	int,		sig		)
+		__field(	unsigned long,	sa_handler	)
+		__field(	unsigned long,	sa_flags	)
+	),
+
+	TP_fast_assign(
+		__entry->sig	= sig;
+		__entry->sa_handler	= (unsigned long)ka->sa.sa_handler;
+		__entry->sa_flags	= ka->sa.sa_flags;
+	),
+
+	TP_printk("sig=%d sa_handler=%lx sa_flags=%lx",
+		  __entry->sig, __entry->sa_handler, __entry->sa_flags)
+);
 #endif /* _TRACE_SIGNAL_H */
 
 /* This part must be outside protection */
diff --git a/kernel/signal.c b/kernel/signal.c
index 82ab077..5615f41 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1860,6 +1860,9 @@ relock:
 			ka = &sighand->action[signr-1];
 		}
 
+		/* Trace the actual delivered signals including SIG_IGN.*/
+		trace_signal_deliver(signr, ka);
+
 		if (ka->sa.sa_handler == SIG_IGN) /* Do nothing.  */
 			continue;
 		if (ka->sa.sa_handler != SIG_DFL) {


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@xxxxxxxxxx
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