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From:   Josh Don <joshdon@google.com>
Date:   Thu, 29 Apr 2021 13:48:01 -0700
Message-ID: <CABk29Nt_xBaoawiyMv1RG+Yzg_a9w5RMc6Zy0ggmS5K-9LzrUA@mail.gmail.com>
Subject: Re: [PATCH 04/19] sched: Prepare for Core-wide rq->lock
To:     Don Hiatt <dhiatt@digitalocean.com>
Cc:     Aubrey Li <aubrey.intel@gmail.com>,
        Aubrey Li <aubrey.li@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        "Hyser,Chris" <chris.hyser@oracle.com>,
        Ingo Molnar <mingo@kernel.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Mel Gorman <mgorman@suse.de>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>
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On Wed, Apr 28, 2021 at 9:41 AM Don Hiatt <dhiatt@digitalocean.com> wrote:
>
> I'm still seeing hard lockups while repeatedly setting cookies on qemu
> processes even with
> the updated patch. If there is any debug you'd like me to turn on,
> just let me know.
>
> Thanks!
>
> don

Thanks for the added context on your repro configuration. In addition
to the updated patch from earlier, could you try the modification to
double_rq_lock() from
https://lkml.kernel.org/r/CABk29NuS-B3n4sbmavo0NDA1OCCsz6Zf2VDjjFQvAxBMQoJ_Lg@mail.gmail.com
? I have a feeling this is what's causing your lockup.

Best,
Josh