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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu, 31 May 2018 09:32:10 -0500
Message-ID: <CA+55aFxasUXmLwb9Mj1j8WSJbmfO1oGkcsZ2hxxbkz_p1gkUfQ@mail.gmail.com>
Subject: Re: Can printk() sleep at runtime?
To:     Petr Mladek <pmladek@suse.com>
Cc:     baijiaju1990@gmail.com, Bjorn Helgaas <bhelgaas@google.com>,
        SergeySenozhatsky <sergey.senozhatsky@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Geert Uytterhoeven <geert+renesas@glider.be>, sboyd@kernel.org,
        Michael Turquette <mturquette@baylibre.com>
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On Thu, May 31, 2018 at 5:05 AM Petr Mladek <pmladek@suse.com> wrote:
>
> Anyway, we need to fix or remove this format. vsprintf-like functions
> are called in any context and nobody expect that they might sleep.

Ack. I guess the argument is that "%pCr" is rare, and none of *those*
users may care, but I do think that doing things wrong as-is.

It's too subtle to have to know you're in a particular locking context
when you use a particular %p modifier.

                   Linus