From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
Sankara Muthukrishnan <sankara.m@gmail.com>,
stable-rt@vger.kernel.org
Subject: [PATCH RT 5/8] timer-fd: Prevent live lock
Date: Wed, 08 Feb 2012 20:59:31 -0500 [thread overview]
Message-ID: <20120209020159.978564482@goodmis.org> (raw)
In-Reply-To: 20120209015926.851312665@goodmis.org
[-- Attachment #1: 0005-timer-fd-Prevent-live-lock.patch --]
[-- Type: text/plain, Size: 893 bytes --]
From: Thomas Gleixner <tglx@linutronix.de>
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 <sankara.m@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
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
next prev parent reply other threads:[~2012-02-09 2:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-09 1:59 [PATCH RT 0/8] [ANNOUNCE] 3.0.20-rt36-rc1 Steven Rostedt
2012-02-09 1:59 ` [PATCH RT 1/8] genirq: Unmask oneshot irqs when thread was not woken Steven Rostedt
2012-02-09 1:59 ` [PATCH RT 2/8] genirq: Handle pending irqs in irq_startup() Steven Rostedt
2012-02-09 1:59 ` [PATCH RT 3/8] signal/x86: Delay calling signals in atomic Steven Rostedt
2012-02-09 1:59 ` [PATCH RT 4/8] x86: Do not disable preemption in int3 on 32bit Steven Rostedt
2012-02-09 1:59 ` Steven Rostedt [this message]
2012-02-09 1:59 ` [PATCH RT 6/8] genirq: Allow disabling of softirq processing in irq thread context Steven Rostedt
2012-02-09 1:59 ` [PATCH RT 7/8] futex: Fix bug on when a requeued RT task times out Steven Rostedt
2012-02-09 1:59 ` [PATCH RT 8/8] Linux 3.0.20-rt36-rc1 Steven Rostedt
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