Commit c7e6d704 authored by Anna-Maria Gleixner's avatar Anna-Maria Gleixner Committed by Thomas Gleixner

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: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190730223828.690771827@linutronix.de
parent a125ecc1
...@@ -213,6 +213,7 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) ...@@ -213,6 +213,7 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
/* We are sharing ->siglock with it_real_fn() */ /* We are sharing ->siglock with it_real_fn() */
if (hrtimer_try_to_cancel(timer) < 0) { if (hrtimer_try_to_cancel(timer) < 0) {
spin_unlock_irq(&tsk->sighand->siglock); spin_unlock_irq(&tsk->sighand->siglock);
hrtimer_cancel_wait_running(timer);
goto again; goto again;
} }
expires = timeval_to_ktime(value->it_value); expires = timeval_to_ktime(value->it_value);
......
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