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: Davide Libenzi <davidel@xmailserver.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Davide Libenzi 2007-06-27 14:09:59 -07:00 committed by Linus Torvalds
parent 58e78475ec
commit f8738c5c52

View File

@ -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;