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Date:   Fri, 20 Jan 2023 16:21:03 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Nicholas Piggin <npiggin@gmail.com>
Cc:     Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        Michael Ellerman <mpe@ellerman.id.au>,
        "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH] exit: Detect and fix irq disabled state in oops
Message-ID: <Y8qxX4iZUZYOaCD0@hirez.programming.kicks-ass.net>
References: <20230120011820.2664120-1-npiggin@gmail.com>
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On Fri, Jan 20, 2023 at 11:18:20AM +1000, Nicholas Piggin wrote:
> If a task oopses with irqs disabled, this can cause various cascading
> problems in the oops path such as sleep-from-invalid warnings, and
> potentially worse.
> 
> Since commit 0258b5fd7c712 ("coredump: Limit coredumps to a single
> thread group"), the unconditional irq enable in coredump_task_exit()
> will "fix" the irq state to be enabled early in do_exit(), so currently
> this may not be triggerable, but that is coincidental and fragile.
> 
> Detect and fix the irqs_disabled() condition in the oops path before
> calling do_exit(), similarly to the way in_atomic() is handled.
> 
> Link: https://lore.kernel.org/lkml/20221004094401.708299-1-npiggin@gmail.com/
> Reported-by: Michael Ellerman <mpe@ellerman.id.au>
> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> Hi Peter,
> 
> Would you consider taking this through the sched tree?

Yep, can do, let me go queue it.