Date:   Mon, 20 Mar 2023 10:05:58 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Alexey Klimov <alexey.klimov@linaro.org>
Cc:     draszik@google.com, peter.griffin@linaro.org,
        willmcvicker@google.com, mingo@kernel.org, ulf.hansson@linaro.org,
        tony@atomide.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, axboe@kernel.dk,
        alim.akhtar@samsung.com, regressions@lists.linux.dev,
        avri.altman@wdc.com, bvanassche@acm.org, klimova@google.com
Subject: Re: [REGRESSION] CPUIDLE_FLAG_RCU_IDLE, blk_mq_freeze_queue_wait()
 and slow-stuck reboots
Message-ID: <20230320090558.GF2194297@hirez.programming.kicks-ass.net>
References: <20230314230004.961993-1-alexey.klimov@linaro.org>
 <20230315111606.GB2006103@hirez.programming.kicks-ass.net>
 <CANgGJDpd4Gm5HhQW__oMAv1yUqSPZ7FSGoQLYTmug=TUk4cn4g@mail.gmail.com>
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On Fri, Mar 17, 2023 at 02:11:25AM +0000, Alexey Klimov wrote:
> On Wed, 15 Mar 2023 at 11:16, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> >
> > (could you wrap your email please)
> 
> Ouch. Sorry.
> 
> > On Tue, Mar 14, 2023 at 11:00:04PM +0000, Alexey Klimov wrote:
> > > #regzbot introduced: 0c5ffc3d7b15 #regzbot title:
> > > CPUIDLE_FLAG_RCU_IDLE, blk_mq_freeze_queue_wait() and slow-stuck
> > > reboots
> > >
> > > The upstream changes are being merged into android-mainline repo and
> > > at some point we started to observe kernel panics on reboot or long
> > > reboot times.
> >
> > On what hardware? I find it somewhat hard to follow this DT code :/
> 
> Pixel 6.

What actual cpuidle driver is that thing using? Is there any out-of-tree
code involved? Mark tells me anything arm64 should be using PSCI, so let
me to stare hard at that again.