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Subject: Re: what trees/branches to test on syzbot
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Guenter Roeck <groeck@google.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "Theodore Ts'o" <tytso@mit.edu>,
        Andrew Morton <akpm@linux-foundation.org>,
        syzkaller <syzkaller@googlegroups.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        David Miller <davem@davemloft.net>,
        Wu Fengguang <fengguang.wu@intel.com>
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From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Message-ID: <b9aa57f5-9204-dc97-bfd6-d53ed2e0ae12@i-love.sakura.ne.jp>
Date:   Tue, 26 Jun 2018 19:54:53 +0900
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On 2018/06/10 7:17, Linus Torvalds wrote:
> On Fri, Jun 8, 2018 at 11:36 PM Tetsuo Handa
> <penguin-kernel@i-love.sakura.ne.jp> wrote:
>> On 2018/01/22 22:32, Dmitry Vyukov wrote:
>>>
>>> FTR I've just dropped linux-next and mmots from syzbot.
>>
>> I hope that we can test linux-next on syzbot, as a tree for testing debug
>> printk() patches.
> 
> I think it would be lovely to get linux-next back eventually, but it
> sounds like it's just too noisy right now, and yes, we should have a
> baseline for the standard tree first.
> 
> But once there's a "this is known for the baseline", I think adding
> linux-next back in and then maybe even have linux-next simply just
> kick out trees that cause problems would be a good idea.
> 
> Right now linux-next only kicks things out based on build issues (or
> extreme merge issues), afaik. But it *would* be good to also have
> things like syzbot do quality control on linux-next.
> 
> Because the more things get found and fixed before they even hit my
> tree, the better.
> 
>                 Linus
> 

I hope we can accept NOW either "reviving linux-next.git" or "allowing debug printk()
patches for linux.git". For example, "INFO: task hung in __sb_start_write" got 900
crashes in 81 days but still unable to find a reproducer. Dmitry tried to reproduce
locally with debug printk() patches but not yet successful. I think that testing with
http://lkml.kernel.org/r/f91e1c82-9693-cca3-4ab7-ecd9d9881fb4@i-love.sakura.ne.jp
on linux.git or linux-next.git is the only realistic way for debugging this bug.
More we postpone revival of the linux-next, more syzbot reports we will get...