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 <CAABZP2ycCjiZ0CySc2Lgr_DnUfuDf1iagEKnWwNEkVkR9-gADA@mail.gmail.com> <YgiEeHzz4JZFszJD@casper.infradead.org>
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From:   Zhouyi Zhou <zhouzhouyi@gmail.com>
Date:   Sun, 13 Feb 2022 12:17:50 +0800
Message-ID: <CAABZP2wNEUpM0OyhpKb+EtKY2RynpeU2N2tu9Jw_9B6iv6jGNQ@mail.gmail.com>
Subject: Re: BUG: sleeping function called from invalid context at include/linux/sched/mm.h:256
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Paul Menzel <pmenzel@molgen.mpg.de>,
        Michael Ellerman <mpe@ellerman.id.au>,
        linuxppc-dev@lists.ozlabs.org, Linux-MM <linux-mm@kvack.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Jason Baron <jbaron@akamai.com>, rcu <rcu@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "Paul E. McKenney" <paulmck@kernel.org>
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Thank Matthew for correcting me

On Sun, Feb 13, 2022 at 12:09 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Sun, Feb 13, 2022 at 11:19:09AM +0800, Zhouyi Zhou wrote:
> > I think the key to the problem lies in your attached console.log
> > (pasted below), at times 0.014987 and 0.015995, I see there are two
> > locks (cpu_hotplug_lock and jump_label_mutex)  holded while
> > kmem_cache_alloc calls __might_resched (0.023356).
>
> Those are both sleeping locks (a percpu_rwsem and mutex, respectively).
> There is no problem with sleeping while holding a mutex or rwsem.
From console.log, I see
[    0.012154][    T1] BUG: sleeping function called from invalid
context at include/linux/sched/mm.h:256
[    0.013128][    T1] in_atomic(): 0, irqs_disabled(): 1, non_block:
0, pid: 1, name: swapper/0
From ___might_sleep, I see

9506         if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
9507              !is_idle_task(current) && !current->non_block_count) ||
9508             system_state == SYSTEM_BOOTING || system_state >
SYSTEM_RUNNING ||
9509             oops_in_progress)
9510                 return;

I guess it is irq_disable which cause the bug.

Thanks
Zhouyi