linux-kernel - Re: [PATCH v2 1/1] powerpc/crash: Use NMI context for printk when starting to crash

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Message-Id: <159168034498.1381411.5705399954174028060.b4-ty@ellerman.id.au>
Date:   Tue,  9 Jun 2020 15:28:58 +1000 (AEST)
From:   Michael Ellerman <patch-notifications@...erman.id.au>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Christophe Leroy <christophe.leroy@....fr>,
        Alexios Zavras <alexios.zavras@...el.com>,
        Leonardo Bras <leobras.c@...il.com>,
        Paul Mackerras <paulus@...ba.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Enrico Weigelt <info@...ux.net>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/1] powerpc/crash: Use NMI context for printk when starting to crash

On Tue, 12 May 2020 18:45:35 -0300, Leonardo Bras wrote:
> Currently, if printk lock (logbuf_lock) is held by other thread during
> crash, there is a chance of deadlocking the crash on next printk, and
> blocking a possibly desired kdump.
> 
> At the start of default_machine_crash_shutdown, make printk enter
> NMI context, as it will use per-cpu buffers to store the message,
> and avoid locking logbuf_lock.

Applied to powerpc/next.

[1/1] powerpc/crash: Use NMI context for printk when starting to crash
      https://git.kernel.org/powerpc/c/af2876b501e42c3fb5174cac9dd02598436f0fdf

cheers