timer-fd: Prevent live lock
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
diff --git a/fs/timerfd.c b/fs/timerfd.c
index 32b644f..1844c97 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -308,7 +308,7 @@
if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
break;
spin_unlock_irq(&ctx->wqh.lock);
- cpu_relax();
+ hrtimer_wait_for_timer(&ctx->tmr);
}
/*