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Date:   Mon, 23 Jan 2023 16:02:39 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc:     Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        linux-perf-users@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [perf] lockdep warning between cpu_add_remove_lock and
 &dev->mutex.
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On Mon, Jan 23, 2023 at 11:10:57PM +0900, Tetsuo Handa wrote:

> After applying your diff, lockdep message changed like below. Is this
> the reason commit 1704f47b50b5 ("lockdep: Add novalidate class for
> dev->mutex conversion") was applied?

No, reason was device probing itself. There should be a thread about
that with Alan Stern some 15 years ago or so.

I'll try and have a look at the new splat later today.