Re: fs: use after free in /proc/pid/mountinfo

[Sasha Levin <sasha.levin@oracle.com>]

On 07/09/2014 06:59 PM, Andrew Morton wrote:
> On Wed, 09 Jul 2014 18:10:47 -0400 Sasha Levin <sasha.levin@oracle.com> wrote:
> 
>> On 07/09/2014 04:31 PM, Andrew Morton wrote:
>>> On Wed, 9 Jul 2014 16:24:06 +0200 Heiko Carstens <heiko.carstens@de.ibm.com> wrote:
>>>
>>>>> 058504edd026 ("fs/seq_file: fallback to vmalloc allocation") is suspected to
>>>>> cause a crash. Actually I can't reprocude the crash nor would I be able to
>>>>> tell how the commit could cause the crash.
>>>>> Anyway, I'll be offline for the next 2.5 weeks. So if Sasha could confirm
>>>>> that reverting the patch actually does fix the crash, please revert the
>>>>> commit, unless somebody else can make sense of the report of course.
>>>>>
>>>>> I'm still wondering how Sasha could reproduce the crash.
>>> This really sucks :(
>>>
>>> I suppose I'll queue up a revert of 058504edd026 as a for-3.16 bandaid.
>>>
>>> Sasha, it would be great if you could delve a bit further into this,
>>> see if we can identify a way for others to reproduce the bug.
>>>
>>> Did you test that little patchlet which Heiko sent?
>>
>> I've been trying, but as there isn't an easy way to reproduce it, breakage
>> elsewhere in -next (there is a long list) is slowing me down. I'll revert
>> back to the -next where I've initially observed this issue and will retry.
>>
> 
> Thanks.  The bug should be present in current mainline.
> 

I've been running mainline for a while, and while I can reproduce a different
bug for Hugh, I can't reproduce this one at all. Not sure how to call it now,
maybe memory corruption from somewhere else (I did find an unrelated memory
corruption couple days ago)?


Thanks,
Sasha