| Subject: timer-fd: Prevent live lock |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Wed, 25 Jan 2012 11:08:40 +0100 |
| |
| 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 |
| --- |
| fs/timerfd.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/fs/timerfd.c |
| +++ b/fs/timerfd.c |
| @@ -311,7 +311,7 @@ SYSCALL_DEFINE4(timerfd_settime, int, uf |
| if (hrtimer_try_to_cancel(&ctx->tmr) >= 0) |
| break; |
| spin_unlock_irq(&ctx->wqh.lock); |
| - cpu_relax(); |
| + hrtimer_wait_for_timer(&ctx->tmr); |
| } |
| |
| /* |
