linux-kernel - Re: [External] Re: [PATCH v2] printk: fix deadlock when kernel panic

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Message-ID: <YCNECIizrMwtjAW2@jagdpanzerIV.localdomain>
Date:   Wed, 10 Feb 2021 11:25:12 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Muchun Song <songmuchun@...edance.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        john.ogness@...utronix.de,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [External] Re: [PATCH v2] printk: fix deadlock when kernel panic

On (21/02/09 09:39), Petr Mladek wrote:
> > > So then this never re-inits the safe_read_lock?
> 
> Yes, but it will also not cause the deadlock.

Right.

> I prefer this approach. It is straightforward because it handles
> read_lock the same way as logbuf_lock.

I'm fine with that approach, but this needs to be in the commit message.
Something like "lose printk_safe message when we think we will deadlock
on printk_safe flush".

	-ss