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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>
hifive-unleashed-5.1
Oleg Nesterov 2011-11-22 21:13:48 +01:00
parent 099469502f
commit 6c303d3ab3
2 changed files with 36 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

85
include/trace/events/signal.h
View File

@ -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 */

22
kernel/signal.c
View File

@ -1054,13 +1054,13 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
struct sigpending *pending;
struct sigqueue *q;
int override_rlimit;
trace_signal_generate(sig, info, t);
int ret = 0, result;
assert_spin_locked(&t->sighand->siglock);
result = TRACE_SIGNAL_IGNORED;
if (!prepare_signal(sig, t, from_ancestor_ns))
return 0;
goto ret;
pending = group ? &t->signal->shared_pending : &t->pending;
/*
@ -1068,8 +1068,11 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
* exactly one non-rt signal, so that we can get more
* detailed information about the cause of the signal.
*/
result = TRACE_SIGNAL_ALREADY_PENDING;
if (legacy_queue(pending, sig))
return 0;
goto ret;
result = TRACE_SIGNAL_DELIVERED;
/*
* fast-pathed signals for kernel-internal things like SIGSTOP
* or SIGKILL.
@ -1127,14 +1130,15 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
* signal was rt and sent by user using something
* other than kill().
*/
trace_signal_overflow_fail(sig, group, info);
return -EAGAIN;
result = TRACE_SIGNAL_OVERFLOW_FAIL;
ret = -EAGAIN;
goto ret;
} 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);
result = TRACE_SIGNAL_LOSE_INFO;
}
}
@ -1142,7 +1146,9 @@ out_set:
signalfd_notify(t, sig);
sigaddset(&pending->signal, sig);
complete_signal(sig, t, group);
return 0;
ret:
trace_signal_generate(sig, info, t, group, result);
return ret;
}
static int send_signal(int sig, struct siginfo *info, struct task_struct *t,