linux-kernel - Re: [PATCH v5] x86: Avoid pr_cont() in show

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Message-ID: <ed59bf3b-705f-8433-f498-0acc2f09ef97@i-love.sakura.ne.jp>
Date:   Thu, 19 Jul 2018 22:54:22 +0900
From:   Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     mingo@...hat.com, linux-kernel@...r.kernel.org, joe@...ches.com,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andy Lutomirski <luto@...capital.net>,
        Borislav Petkov <bp@...e.de>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v5] x86: Avoid pr_cont() in show_opcodes().

On 2018/07/18 20:57, Ingo Molnar wrote:
> 
> * Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp> wrote:
> 
>> Since syzbot is confused by concurrent printk() messages [1],
>> this patch changes show_opcodes() to use %ph format string.
>>
>> When we start adding prefix to each line of printk() output,
>> we will be able to handle concurrent printk() messages.
>>
>> [1] https://syzkaller.appspot.com/text?tag=CrashReport&x=139d342c400000
>>
>> Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
>> Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
> 
> Wasn't that variant of the patch written by Rasmus?

Rasmus Villemoes taught me that we can use "%*ph" format string and pass
length as arguments for "*" part. Then, since Joe Perches suggested me to
use #define for length variable, I updated to use "#define length immediate"
and replaced "%*ph" with "%" __strigify(length) "ph" and removed length from
arguments. That is v5 patch.

> 
> If so then the changelog should start with:
> 
>  From: Rasmus Villemoes <linux@...musvillemoes.dk>

OK. I posted v6 patch with From: line updated.

> 
> Thanks,
> 
> 	Ingo
>