Commit 92413d77 authored Jul 25, 2008 by Oleg Nesterov Committed by Linus Torvalds Jul 25, 2008

signals: dequeue_signal: don't check SIGNAL_GROUP_EXIT when setting SIGNAL_STOP_DEQUEUED



dequeue_signal() checks SIGNAL_GROUP_EXIT before setting
SIGNAL_STOP_DEQUEUED.  This was added by
788e05a6 a long ago to avoid the
coredump/SIGSTOP race.

Since then the related code was changed, and now this subtle check is both
incomplete and unneeded at the same time.  It is incomplete because
nowadays exec() doesn't set SIGNAL_GROUP_EXIT, so in fact we should check
signal_group_exit() to avoid a similar race.  Fortunately, we doesn't need
the check at all.  The only function which relies on SIGNAL_STOP_DEQUEUED
is do_signal_stop(), and it ignores this flag if signal_group_exit() == T,
this covers the SIGNAL_GROUP_EXIT case.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 3854a771

kernel/signal.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -454,7 +454,6 @@ int dequeue_signal(struct task_struct tsk, sigset_t mask, siginfo_t *info)
		* is to alert stop-signal processing code when another
		* processor has come along and cleared the flag.
		*/
		if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT))
		tsk->signal->flags \|= SIGNAL_STOP_DEQUEUED;
		}
		if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {

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