From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 4/6] posix-cpu-timers: Force next_expiration recalc after timer reset
Date: Wed, 16 Jun 2021 11:23:33 +0200 [thread overview]
Message-ID: <YMnDFQ9bvVPHu/kJ@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210604113159.26177-5-frederic@kernel.org>
On Fri, Jun 04, 2021 at 01:31:57PM +0200, Frederic Weisbecker wrote:
> @@ -647,8 +651,6 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
> if (unlikely(timer->it.cpu.firing)) {
> timer->it.cpu.firing = -1;
> ret = TIMER_RETRY;
> - } else {
> - cpu_timer_dequeue(ctmr);
> }
>
> /*
> @@ -713,9 +715,13 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
> * For a timer with no notification action, we don't actually
> * arm the timer (we'll just fake it for timer_gettime).
> */
> - cpu_timer_setexpires(ctmr, new_expires);
> - if (new_expires != 0 && val < new_expires) {
> - arm_timer(timer, p);
> + if (new_expires != 0) {
> + cpu_timer_dequeue(ctmr);
> + cpu_timer_setexpires(ctmr, new_expires);
> + if (val < new_expires)
> + arm_timer(timer, p);
> + } else {
> + disarm_timer(timer, p);
> }
>
> unlock_task_sighand(p, &flags);
AFAICT there's an error path in between where you've removed
cpu_timer_dequeue() and added it back. This error path will now leave
the timer enqueued.
next prev parent reply other threads:[~2021-06-16 9:23 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 11:31 [PATCH 0/6] posix-cpu-timers: Bunch of fixes Frederic Weisbecker
2021-06-04 11:31 ` [PATCH 1/6] posix-cpu-timers: Fix rearm racing against process tick Frederic Weisbecker
2021-06-09 11:54 ` Frederic Weisbecker
2021-06-11 11:49 ` Peter Zijlstra
2021-06-11 12:37 ` Frederic Weisbecker
2021-06-04 11:31 ` [PATCH 2/6] posix-cpu-timers: Don't start process wide cputime counter if timer is disabled Frederic Weisbecker
2021-06-09 12:18 ` Frederic Weisbecker
2021-06-10 10:24 ` Frederic Weisbecker
2021-06-16 8:51 ` Peter Zijlstra
2021-06-16 10:51 ` Frederic Weisbecker
2021-06-16 11:26 ` Peter Zijlstra
2021-06-16 11:50 ` Peter Zijlstra
2021-06-04 11:31 ` [PATCH 3/6] posix-cpu-timers: Force next_expiration recalc after timer deletion Frederic Weisbecker
2021-06-16 9:16 ` Peter Zijlstra
2021-06-04 11:31 ` [PATCH 4/6] posix-cpu-timers: Force next_expiration recalc after timer reset Frederic Weisbecker
2021-06-16 9:23 ` Peter Zijlstra [this message]
2021-06-16 11:21 ` Frederic Weisbecker
2021-06-16 11:33 ` Peter Zijlstra
2021-06-04 11:31 ` [PATCH 5/6] posix-cpu-timers: Force next expiration recalc after early timer firing Frederic Weisbecker
2021-06-16 9:42 ` Peter Zijlstra
2021-06-16 11:59 ` Frederic Weisbecker
2021-06-16 13:23 ` Peter Zijlstra
2021-06-16 14:53 ` Frederic Weisbecker
2021-06-04 11:31 ` [PATCH 6/6] posix-cpu-timers: Force next expiration recalc after itimer reset Frederic Weisbecker
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