sigwait eats blocked default-ignore signals

While a signal is blocked, it must be posted even if its action is
SIG_IGN or is SIG_DFL with the default action to ignore.  This works
right most of the time, but is broken when a sigwait (rt_sigtimedwait)
is in progress.  This changes the early-discard check to respect
real_blocked.  ~blocked is the set to check for "should wake up now",
but ~(blocked|real_blocked) is the set for "blocked" semantics as
defined by POSIX.

This fixes bugzilla entry 9347, see

	http://bugzilla.kernel.org/show_bug.cgi?id=9347

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 909a0cc6bc70..afa4f781f924 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -55,7 +55,7 @@ static int sig_ignored(struct task_struct *t, int sig)
          * signal handler may change by the time it is
          * unblocked.
          */
-        if (sigismember(&t->blocked, sig))
+        if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
                 return 0;
 
         /* Is it explicitly or implicitly ignored? */