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[tip:perf/core] tracepoint: Add signal loss events
- From: tip-bot for Masami Hiramatsu <mhiramat at redhat dot com>
- To: linux-tip-commits at vger dot kernel dot org
- Cc: linux-kernel at vger dot kernel dot org, hpa at zytor dot com, mingo at redhat dot com, roland at redhat dot com, dle-develop at lists dot sourceforge dot net, oleg at redhat dot com, tglx at linutronix dot de, jbaron at redhat dot com, mhiramat at redhat dot com, mingo at elte dot hu, systemtap at sources dot redhat dot com
- Date: Thu, 26 Nov 2009 10:25:07 GMT
- Subject: [tip:perf/core] tracepoint: Add signal loss events
- Git-commit-id: ba005e1f417295d28cd1563ab82bc33af07fb16a
- References: <20091124215658.30449.9934.stgit@dhcp-100-2-132.bos.redhat.com>
- Reply-to: mingo at redhat dot com, hpa at zytor dot com, linux-kernel at vger dot kernel dot org, roland at redhat dot com, dle-develop at lists dot sourceforge dot net, oleg at redhat dot com, tglx at linutronix dot de, jbaron at redhat dot com, mhiramat at redhat dot com, systemtap at sources dot redhat dot com, mingo at elte dot hu
Commit-ID: ba005e1f417295d28cd1563ab82bc33af07fb16a
Gitweb: http://git.kernel.org/tip/ba005e1f417295d28cd1563ab82bc33af07fb16a
Author: Masami Hiramatsu <mhiramat@redhat.com>
AuthorDate: Tue, 24 Nov 2009 16:56:58 -0500
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 26 Nov 2009 10:55:38 +0100
tracepoint: Add signal loss events
Add signal_overflow_fail and signal_lose_info tracepoints
for signal-lost events.
Changes in v3:
- Add docbook style comments
Changes in v2:
- Use siginfo string macro
Suggested-by: Roland McGrath <roland@redhat.com>
Reviewed-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Oleg Nesterov <oleg@redhat.com>
LKML-Reference: <20091124215658.30449.9934.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/trace/events/signal.h | 68 +++++++++++++++++++++++++++++++++++++++++
kernel/signal.c | 19 ++++++++---
2 files changed, 82 insertions(+), 5 deletions(-)
diff --git a/include/trace/events/signal.h b/include/trace/events/signal.h
index a6d71de..a510b75 100644
--- a/include/trace/events/signal.h
+++ b/include/trace/events/signal.h
@@ -99,6 +99,74 @@ TRACE_EVENT(signal_deliver,
__entry->sig, __entry->errno, __entry->code,
__entry->sa_handler, __entry->sa_flags)
);
+
+/**
+ * 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.
+ */
+TRACE_EVENT(signal_overflow_fail,
+
+ 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_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.
+ */
+TRACE_EVENT(signal_lose_info,
+
+ 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)
+);
#endif /* _TRACE_SIGNAL_H */
/* This part must be outside protection */
diff --git a/kernel/signal.c b/kernel/signal.c
index 349d449..93e72e5 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -897,12 +897,21 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
break;
}
} else if (!is_si_special(info)) {
- if (sig >= SIGRTMIN && info->si_code != SI_USER)
- /*
- * Queue overflow, abort. We may abort if the signal was rt
- * and sent by user using something other than kill().
- */
+ if (sig >= SIGRTMIN && info->si_code != SI_USER) {
+ /*
+ * Queue overflow, abort. We may abort if the
+ * signal was rt and sent by user using something
+ * other than kill().
+ */
+ trace_signal_overflow_fail(sig, group, info);
return -EAGAIN;
+ } else {
+ /*
+ * This is a silent loss of information. We still
+ * send the signal, but the *info bits are lost.
+ */
+ trace_signal_lose_info(sig, group, info);
+ }
}
out_set: