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Date:   Sat, 24 Sep 2022 00:40:04 -0700 (PDT)
From:   Hugh Dickins <hughd@google.com>
To:     Borislav Petkov <bp@alien8.de>
cc:     Nathan Chancellor <nathan@kernel.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: INFO: task systemd-udevd:94 blocked for more than 120 seconds.
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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.

Hugh