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Date: Thu, 10 May 2018 13:22:06 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        syzkaller <syzkaller@googlegroups.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Fengguang Wu <fengguang.wu@intel.com>, linux-kernel@vger.kernel.org
Subject: Re: printk feature for syzbot?
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On (04/26/18 12:06), Petr Mladek wrote:
> 
> > Petr, Steven, Fengguang, what do you think? Do you have any objections?
> > Ideas?
> 
> I wonder if we could create some mechanism that would help to extend
> struct printk_log easier in the future.

Hm, interesting idea.

> I know only about crash tool implementation. It uses information provided
> by log_buf_vmcoreinfo_setup(). The size of the structure is already
> public. Therefore crash should be able to find all existing information
> even if we increase the size of the structure.
> 
> log_buf_vmcoreinfo_setup() even allows to inform about newly added
> structure items. We could probably extend it to inform also about
> the offset of the new optional elements.

I vaguely remember that the last time Thomas Gleixner modified
printk_log you managed to find a case that broke crash tool.
... Or may be I'm mistaken.

> I am not sure about other tools. But I think that it should be
> doable.

Good. So there are no objections, so far.

Tetsuo, Dmitry, care to send a patch?

	-ss