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Subject: Re: [PATCH v3 05/12] usb: otg-fsm: Fix hrtimer list corruption
To:     Peter Chen <peter.chen@kernel.org>
Cc:     Thierry Reding <treding@nvidia.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Sebastian Reichel <sre@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Felipe Balbi <balbi@kernel.org>,
        David Heidelberg <david@ixit.cz>, devicetree@vger.kernel.org,
        linux-pm@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org
References: <20210704225433.32029-1-digetx@gmail.com>
 <20210704225433.32029-6-digetx@gmail.com> <20210706005739.GA19143@nchen>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <04a679be-ec66-f71f-5b61-59b8ef82e128@gmail.com>
Date:   Tue, 6 Jul 2021 04:15:38 +0300
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06.07.2021 03:57, Peter Chen пишет:
> On 21-07-05 01:54:26, Dmitry Osipenko wrote:
>> The HNP work can be re-scheduled while it's still in-fly. This results in
>> re-initialization of the busy work, resetting the hrtimer's list node of
>> the work and crashing kernel with null dereference within kernel/timer
>> once work's timer is expired. It's very easy to trigger this problem by
>> re-plugging USB cable quickly. Initialize HNP work only once to fix this
>> trouble.
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> 
> Acked-by: Peter Chen <peter.chen@kernel.org>
> 
> It is better to append kernel dump if you have v4 patchset.

The stacktrace isn't very useful because it crashes within a hrtimer
code from a work thread, i.e. it doesn't point at usb at all. It
actually took me some effort to find where the bug was.