linux-kernel - Re: Bug: d0e936adbd22 crashes at boot

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Date:   Fri, 3 Sep 2021 08:15:29 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        LKML <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Len Brown <lenb@...nel.org>, inux-pm@...r.kernel.org
Subject: Re: Bug: d0e936adbd22 crashes at boot

On 9/3/21 8:13 AM, Srinivas Pandruvada wrote:
> Hi Axboe,
> 
> Thanks for reporting.
> On Fri, 2021-09-03 at 07:36 -0600, Jens Axboe wrote:
>> Hi,
>>
>> Booting Linus's tree causes a crash on my laptop, an x1 gen9. This was
>> a bit
>> difficult to pin down as it crashes before the display is up, but I
>> managed
>> to narrow it down to:
>>
>> commit d0e936adbd2250cb03f2e840c6651d18edc22ace
>> Author: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
>> Date:   Thu Aug 19 19:40:06 2021 -0700
>>
>>     cpufreq: intel_pstate: Process HWP Guaranteed change notification
>>
>> which crashes with a NULL pointer deref in notify_hwp_interrupt() ->
>> queue_delayed_work_on().
>>
>> Reverting this change makes the laptop boot fine again.
>>
> Does this change fixes your issue?

I would assume so, as it's crashing on cpudata == NULL :-)

But why is it NULL? Happy to test patches, but the below doesn't look like
a real fix and more of a work-around.

-- 
Jens Axboe