From: Oleg Nesterov <oleg@tv-sign.ru>

do_sigaction() returns -ERESTARTNOINTR if signal_pending(). The comment says:

	* If there might be a fatal signal pending on multiple
	* threads, make sure we take it before changing the action.

I think this is not needed. We should only worry about SIGNAL_GROUP_EXIT case,
bit it implies a pending SIGKILL which can't be cleared by do_sigaction.

Kill this special 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>
---

 kernel/signal.c |    9 ---------
 1 files changed, 9 deletions(-)

diff -puN kernel/signal.c~do_sigaction-dont-worry-about-signal_pending kernel/signal.c
--- a/kernel/signal.c~do_sigaction-dont-worry-about-signal_pending
+++ a/kernel/signal.c
@@ -2296,15 +2296,6 @@ int do_sigaction(int sig, struct k_sigac
 	k = &current->sighand->action[sig-1];
 
 	spin_lock_irq(&current->sighand->siglock);
-	if (signal_pending(current)) {
-		/*
-		 * If there might be a fatal signal pending on multiple
-		 * threads, make sure we take it before changing the action.
-		 */
-		spin_unlock_irq(&current->sighand->siglock);
-		return -ERESTARTNOINTR;
-	}
-
 	if (oact)
 		*oact = *k;
 
_