From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752912AbeC1KHx (ORCPT ); Wed, 28 Mar 2018 06:07:53 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:50181 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752754AbeC1KHw (ORCPT ); Wed, 28 Mar 2018 06:07:52 -0400 From: Sebastian Andrzej Siewior To: linux-rt-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Steven Rostedt , Sebastian Andrzej Siewior , stable-rt@vger.kernel.org Subject: [PATCH RT 1/3] alarmtimer: Prevent live lock in alarm_cancel() Date: Wed, 28 Mar 2018 12:07:44 +0200 Message-Id: <20180328100746.18668-1-bigeasy@linutronix.de> X-Mailer: git-send-email 2.16.3 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If alarm_try_to_cancel() requires a retry, then depending on the priority setting the retry loop might prevent timer callback completion on RT. Prevent that by waiting for completion on RT, no change for a non RT kernel. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior --- kernel/time/alarmtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index ec09ce9a6012..ede5ef787865 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -429,7 +429,7 @@ int alarm_cancel(struct alarm *alarm) int ret =3D alarm_try_to_cancel(alarm); if (ret >=3D 0) return ret; - cpu_relax(); + hrtimer_wait_for_timer(&alarm->timer); } } EXPORT_SYMBOL_GPL(alarm_cancel); --=20 2.16.3