Commit-ID: c7e6d704a0097e59667495cf52dcc4e1085e620b
Gitweb: https://git.kernel.org/tip/c7e6d704a0097e59667495cf52dcc4e1085e620b
Author: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
AuthorDate: Wed, 31 Jul 2019 00:33:51 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 1 Aug 2019 20:51:24 +0200
itimers: Prepare for PREEMPT_RT
Use the hrtimer_cancel_wait_running() synchronization mechanism to prevent
priority inversion and live locks on PREEMPT_RT.
As a benefit the retry loop gains the missing cpu_relax() on !RT.
[ tglx: Split out of combo patch ]
Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20190730223828.690771827@xxxxxxxxxxxxx
---
kernel/time/itimer.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index 02068b2d5862..9d26fd4ba4c0 100644
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -213,6 +213,7 @@ again:
/* We are sharing ->siglock with it_real_fn() */
if (hrtimer_try_to_cancel(timer) < 0) {
spin_unlock_irq(&tsk->sighand->siglock);
+ hrtimer_cancel_wait_running(timer);
goto again;
}
expires = timeval_to_ktime(value->it_value);
|