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Date:   Sat, 24 Sep 2022 10:16:51 +0200
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Subject: Re: INFO: task systemd-udevd:94 blocked for more than 120 seconds.
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To:     Hugh Dickins <hughd@google.com>, Borislav Petkov <bp@alien8.de>
Cc:     Nathan Chancellor <nathan@kernel.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
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From:   Daniel Lezcano <daniel.lezcano@linaro.org>
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Hi Hugh,

On 24/09/2022 09:40, Hugh Dickins wrote:
> On Fri, 23 Sep 2022, Borislav Petkov wrote:
>> On Fri, Sep 23, 2022 at 12:18:56PM -0700, Nathan Chancellor wrote:
>>> I have not seen a stacktrace like this on my machines (although I
>>> suspect that is because I don't have CONFIG_DETECT_HUNG_TASK enabled in
>>> my configs) but my Honeycomb LX2 hangs while booting after commit
>>> 78ffa3e58d93 ("thermal/core: Add a generic thermal_zone_get_trip()
>>> function") according to my bisect, which certainly seems like it could
>>> be related to the trace you are seeing.
>>
>> Don't you just love how well our community works - one reports a bug and
>> someone else has already bisected it and thus saves one the work?!
>>
>> :-)))
>>
>> Thanks Nathan, I can confirm your bisection. The commit above doesn't
>> revert cleanly ontop of linux-next so I tried it and the patch before
>> it:
>>
>> 78ffa3e58d93 ("thermal/core: Add a generic thermal_zone_get_trip() function")	<- BAD
>> 62022c15f627 ("Merge branch 'pm-opp' into linux-next")				<- GOOD
>>
>> so it looks like that one is somehow b0rked.
> 
> Yes, Nathan was alert, and saved me too from bisecting failure to boot
> linux-next in another thread.
> 
> And I see from
> https://lore.kernel.org/lkml/c85a77a3-409b-3e83-08a7-ac7e1888790d@samsung.com/
> that Marek also found it: and tried to fix it, but found it goes too wide.
> 
> I made a patch of the offending series with
> git diff 78ffa3e58d93^ 2b109cffe683
> and then reverted that cleanly from next-20220923: works for me.

Thanks for investigating. I believe I found from where is coming the 
deadlock. I'll send a fix for that.


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