From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757569AbcAYTJU (ORCPT ); Mon, 25 Jan 2016 14:09:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46908 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757063AbcAYTJR (ORCPT ); Mon, 25 Jan 2016 14:09:17 -0500 Date: Mon, 25 Jan 2016 20:09:15 +0100 From: Oleg Nesterov To: Sasha Levin Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org Subject: Re: [PATCH] signals: work around random wakeups in sigsuspend() Message-ID: <20160125190915.GA9362@redhat.com> References: <1453735306-13519-1-git-send-email-sasha.levin@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1453735306-13519-1-git-send-email-sasha.levin@oracle.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/25, Sasha Levin wrote: > > A random wakeup can get us out of sigsuspend() without TIF_SIGPENDING > being set. and TIF_RESTORE_SIGMASK is just wrong in this case. I'd say this is the bugfix, not work-around ;) > Avoid that by making sure we were signaled, like sys_pause() does. > > Signed-off-by: Sasha Levin Acked-by: Oleg Nesterov Thanks Sasha. > --- > kernel/signal.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/kernel/signal.c b/kernel/signal.c > index 5da9180..3256c7e 100644 > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -3528,8 +3528,10 @@ static int sigsuspend(sigset_t *set) > current->saved_sigmask = current->blocked; > set_current_blocked(set); > > - __set_current_state(TASK_INTERRUPTIBLE); > - schedule(); > + while (!signal_pending(current)) { > + __set_current_state(TASK_INTERRUPTIBLE); > + schedule(); > + } > set_restore_sigmask(); > return -ERESTARTNOHAND; > } > -- > 1.7.10.4 >