From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757519Ab2BICCu (ORCPT ); Wed, 8 Feb 2012 21:02:50 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:49706 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757025Ab2BICCC (ORCPT ); Wed, 8 Feb 2012 21:02:02 -0500 X-Authority-Analysis: v=2.0 cv=T9kOvo2Q c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=UBy9sU4F98IA:10 a=50Qc3saDhTEA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=pGLkceISAAAA:8 a=VwQbUJbxAAAA:8 a=meVymXHHAAAA:8 a=Y6fbuv1wHoTy9iPxX6AA:9 a=Zh68SRI7RUMA:10 a=MSl-tDqOz04A:10 a=jeBq3FmKZ4MA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-Id: <20120209020159.978564482@goodmis.org> User-Agent: quilt/0.50-1 Date: Wed, 08 Feb 2012 20:59:31 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , John Kacur , Sankara Muthukrishnan , stable-rt@vger.kernel.org Subject: [PATCH RT 5/8] timer-fd: Prevent live lock References: <20120209015926.851312665@goodmis.org> Content-Disposition: inline; filename=0005-timer-fd-Prevent-live-lock.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner If hrtimer_try_to_cancel() requires a retry, then depending on the priority setting te retry loop might prevent timer callback completion on RT. Prevent that by waiting for completion on RT, no change for a non RT kernel. Reported-by: Sankara Muthukrishnan Signed-off-by: Thomas Gleixner Cc: stable-rt@vger.kernel.org Signed-off-by: Steven Rostedt --- fs/timerfd.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/timerfd.c b/fs/timerfd.c index dffeb37..57f0e4e 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -313,7 +313,7 @@ SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags, if (hrtimer_try_to_cancel(&ctx->tmr) >= 0) break; spin_unlock_irq(&ctx->wqh.lock); - cpu_relax(); + hrtimer_wait_for_timer(&ctx->tmr); } /* -- 1.7.8.3