signals: check ->group_stop_count after tracehook_get_signal()

Move the call to do_signal_stop() down, after tracehook call.  This makes
->group_stop_count condition visible to tracers before do_signal_stop()
will participate in this group-stop.

Currently the patch has no effect, tracehook_get_signal() always returns 0.

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

diff --git a/kernel/signal.c b/kernel/signal.c
index 4a9d763..1814e68 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1840,11 +1840,6 @@ relock:
 
        for (;;) {
                struct k_sigaction *ka;
-
-               if (unlikely(signal->group_stop_count > 0) &&
-                   do_signal_stop(0))
-                       goto relock;
-
                /*
                 * Tracing can induce an artifical signal and choose sigaction.
                 * The return value in @signr determines the default action,
@@ -1856,6 +1851,10 @@ relock:
                if (unlikely(signr != 0))
                        ka = return_ka;
                else {
+                       if (unlikely(signal->group_stop_count > 0) &&
+                           do_signal_stop(0))
+                               goto relock;
+
                        signr = dequeue_signal(current, &current->blocked,
                                               info);