Subject: Re: [PATCH v2] inotify: Convert to using per-namespace limits
To: "Eric W. Biederman" <ebiederm@xmission.com>
References: <20161010164046.GG24081@quack2.suse.cz>
 <1476171382-11911-1-git-send-email-kernel@kyup.com>
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 <e86b3a4f-51d5-ea61-93f3-883fe2dbcf34@gmail.com>
Cc: containers@lists.linux-foundation.org, jack@suse.cz,
        linux-kernel@vger.kernel.org, serge@hallyn.com
From: Nikolay Borisov <n.borisov.lkml@gmail.com>
Message-ID: <100ecab5-6656-9ed6-c0f4-b9c97eae506a@gmail.com>
Date: Thu, 8 Dec 2016 10:14:50 +0200
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On  8.12.2016 08:58, Nikolay Borisov wrote:
> 
> 
> On  8.12.2016 03:40, Eric W. Biederman wrote:
>> Nikolay Borisov <kernel@kyup.com> writes:
>>
>>> Gentle ping, now that rc1 has shipped and Jan's sysctl concern hopefully
>>> resolved.
>>
>> After getting slowed down by some fixes I am now taking a hard look at
>> your patch in the hopes of merging it.
>>
>> Did you happen to see the kbuild test roboot boot failures and did you
>> happen to look into what caused them?  I have just skimmed them and it
>> appears to be related to your patch.
> 
> I saw them in the beginning but they did look like a generic memory
> corruption and I believe at the time those patches were submitted there
> was a lingering memory corruption hitting various patches. Thus I didn't
> think it was related to my patches. I've since left my work so been
> taking a bit of time off and haven't looked really hard, so those
> patches have been kind of lingering.
> 
> 
> But now that you mention it I will try and take a second look to see
> what might cause the memory corruption? Is there a way to force 0day to
> re-run them to see whether the failure was indeed caused by my patches
> or were intermittent?

Ok, I took another look into the report but bear in mind that the
corruption indeed happened in retire_userns_sysctls. But also this row
in the report leads me to believe it's not my patch that's the culprit:

[   65.527277] INFO: Allocated in setup_userns_sysctls+0x3f/0xa6 age=5
cpu=1 pid=418
[   65.558397] INFO: Freed in free_ctx+0x1d/0x20 age=6 cpu=0 pid=19


So a free_ctx function did free it originally, likely causing the
corruption. And there is no such function involved in the code I'm touching.
> 
> Regards,
> Nikolay
> 
> 
>>
>> Eric
>>
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