From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 5/8] timer-fd: Prevent live lock Date: Wed, 08 Feb 2012 20:59:31 -0500 Message-ID: <20120209020159.978564482@goodmis.org> References: <20120209015926.851312665@goodmis.org> Cc: Thomas Gleixner , Carsten Emde , John Kacur , Sankara Muthukrishnan , stable-rt@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Content-Disposition: inline; filename=0005-timer-fd-Prevent-live-lock.patch Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.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