signal: sys_pause() should check signal_pending()

ERESTART* is always wrong without TIF_SIGPENDING. Teach sys_pause()
to handle the spurious wakeup correctly.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index ad5e818baacc..86c32b884f8e 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3023,8 +3023,10 @@ SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
 
 SYSCALL_DEFINE0(pause)
 {
-        current->state = TASK_INTERRUPTIBLE;
-        schedule();
+        while (!signal_pending(current)) {
+                current->state = TASK_INTERRUPTIBLE;
+                schedule();
+        }
         return -ERESTARTNOHAND;
 }