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Commit f8738c5c authored by Davide Libenzi's avatar Davide Libenzi Committed by Linus Torvalds
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avoid spurious POLLIN returns in signalfd 



The new code in kernel/signal.c does not allow fetching private signals
from another task.  This patch avoid spurious POLLIN returns from a
signalfd poll(2) operation.

Signed-off-by: default avatarDavide Libenzi <davidel@xmailserver.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 58e78475

fs/signalfd.c

+2 −1
Original line number Diff line number Diff line
@@ -133,7 +133,8 @@ static unsigned int signalfd_poll(struct file *file, poll_table *wait) 
	 * the peer disconnects.

	 */

	if (signalfd_lock(ctx, &lk)) {

		if (next_signal(&lk.tsk->pending, &ctx->sigmask) > 0 ||

		if ((lk.tsk == current &&

		     next_signal(&lk.tsk->pending, &ctx->sigmask) > 0) ||

		    next_signal(&lk.tsk->signal->shared_pending,

				&ctx->sigmask) > 0)

			events |= POLLIN;