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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>
This commit is contained in:
Masami Hiramatsu 2009-11-24 16:56:58 -05:00 committed by Ingo Molnar
parent f9d4257e01
commit ba005e1f41
2 changed files with 82 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
include/trace/events/signal.h
View File

@ -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 */

19
kernel/signal.c
View File

@ -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: