linux-kernel - Re: [PATCH] sched/vtime: Prevent unstable evaluation of WARN(vtime->state)

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Message-ID: <20191230173943.GA12625@lenoir>
Date:   Mon, 30 Dec 2019 18:39:44 +0100
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Chris Wilson <chris@...is-wilson.co.uk>
Cc:     linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH] sched/vtime: Prevent unstable evaluation of
 WARN(vtime->state)

On Mon, Dec 30, 2019 at 09:04:36AM +0000, Chris Wilson wrote:
> As the vtime is sampled under loose seqcount protection by kcpustat, the
> vtime fields may change as the code flows. Where logic dictates a field
> has a static value, use a READ_ONCE.
> 
> Fixes: 74722bb223d0 ("sched/vtime: Bring up complete kcpustat accessor")
> Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
> Cc: Frederic Weisbecker <frederic@...nel.org>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Ingo Molnar <mingo@...nel.org>

Oh thanks for taking the time to make it a proper patch!
Looks good, I'm relaying it.