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Date:   Tue, 6 Jun 2023 22:39:59 +0200
From:   Oleg Nesterov <oleg@redhat.com>
To:     Wander Lairson Costa <wander@redhat.com>
Cc:     "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
        Brian Cain <bcain@quicinc.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Stafford Horne <shorne@gmail.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Liam R. Howlett" <Liam.Howlett@oracle.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Andrei Vagin <avagin@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Daniel Bristot de Oliveira <bristot@kernel.org>,
        Yu Zhao <yuzhao@google.com>,
        Alexey Gladkov <legion@kernel.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Yang Shi <shy828301@gmail.com>,
        open list <linux-kernel@vger.kernel.org>,
        Hu Chunyu <chuhu@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Steven Rostedt <rostedt@goodmis.org>,
        Luis Goncalves <lgoncalv@redhat.com>
Subject: Re: [PATCH v9] kernel/fork: beware of __put_task_struct calling
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On 06/05, Wander Lairson Costa wrote:
>
> Thanks. I found an unrelated earlier splat in the console code. That's
> why I couldn't reproduce it in the stock kernel.

As expected...

So... Not sure what can I say ;) can you verify that this patch doesn't solve
the issues with CONFIG_PROVE_RAW_LOCK_NESTING pointed out by Sebastian? Using
stress-ng or anything else.

This is not that bad, unless I am totally confused the current code (without
your patch) has the same problem (otherwise we wouldn't need this fix).

But perhaps you can make 2/2 which adds the DEFINE_WAIT_OVERRIDE_MAP() hack
as Peter suggested?

Oleg.