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Commit ba005e1f authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
Browse files

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: default avatarRoland McGrath <roland@redhat.com>
Reviewed-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Acked-by: default avatarRoland 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: default avatarIngo Molnar <mingo@elte.hu>
parent f9d4257e

include/trace/events/signal.h

+68 −0
Original line number Diff line number Diff line
@@ -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 */

kernel/signal.c

+14 −5
Original line number Diff line number Diff line
@@ -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)

		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().

			 * 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: