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From: Peter Zijlstra <peterz@infradead.org>
To: Juri Lelli <juri.lelli@redhat.com>
Cc: mingo@redhat.com, linux-kernel@vger.kernel.org,
	vincent.guittot@linaro.org, rostedt@goodmis.org,
	dietmar.eggemann@arm.com, bristot@redhat.com, bsegall@google.com,
	mgorman@suse.de, Mark Simmons <msimmons@redhat.com>
Subject: Re: [PATCH] sched/rt: Fix double enqueue caused by rt_effective_prio
Date: Thu, 8 Jul 2021 13:35:26 +0200	[thread overview]
Message-ID: <YObi/nNu115qg5Rr@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210701091431.256457-1-juri.lelli@redhat.com>

On Thu, Jul 01, 2021 at 11:14:31AM +0200, Juri Lelli wrote:
> Looks like this survives the test case (and regression testing), but I'm
> still not fully convinced that the above statement "Concurrent priority
> inheritance handling is still safe and will eventually converge to a new
> state by following the inheritance chain(s)" is actually sound.

I think we good there. rt_mutex_adjust_prio_chain() updates ->prio in
step 7 and calls rt_mutex_setprio() in step 11.

So if we race against __sched_setschedule() and observe the old value,
step 11 will follow up and correct us.

      parent reply	other threads:[~2021-07-08 11:36 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-01  9:14 [PATCH] sched/rt: Fix double enqueue caused by rt_effective_prio Juri Lelli
2021-07-06 14:48 ` Dietmar Eggemann
2021-07-07  8:47   ` Juri Lelli
2021-07-08 10:06 ` Peter Zijlstra
2021-07-08 10:26   ` Peter Zijlstra
2021-07-09  8:33     ` Juri Lelli
2021-08-02  7:35       ` Juri Lelli
2021-08-02 13:38         ` Peter Zijlstra
2021-07-08 11:35 ` Peter Zijlstra [this message]

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