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

From: Oleg Nesterov
Date: Sun Mar 23 2014 - 15:39:21 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

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 30bfe53..a615110 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3082,8 +3082,15 @@ EXPORT_SYMBOL(allow_signal);

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

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