[PATCH RESEND 09/11] signals: disallow_signal() should flush the potentially pending signal

From: Oleg Nesterov
Date: Mon Apr 14 2014 - 11:45:14 EST


disallow_signal() simply sets SIG_IGN, this is not enough and
recalc_sigpending() is simply pointless because in can never
change the state of TIF_SIGPENDING.

If we ignore a signal, we also need to do flush_sigqueue_mask() for
the case when this signal is pending, this way recalc_sigpending()
can actually clear TIF_SIGPENDING and we do not "leak" the allocated
siginfo's.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
kernel/signal.c | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 3eec27b..4bab1b7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3084,8 +3084,15 @@ EXPORT_SYMBOL(allow_signal);

void disallow_signal(int sig)
{
+ sigset_t mask;
+
+ sigemptyset(&mask);
+ sigaddset(&mask, sig);
+
spin_lock_irq(&current->sighand->siglock);
current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
+ flush_sigqueue_mask(&mask, &current->signal->shared_pending);
+ flush_sigqueue_mask(&mask, &current->pending);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
}
--
1.5.5.1

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