Re: mm: shm: hang in shmem_fallocate

[Sasha Levin]

On 06/27/2014 01:59 AM, Hugh Dickins wrote:
>> > First, this:
>> > 
>> > [  681.267487] BUG: unable to handle kernel paging request at ffffea0003480048
>> > [  681.268621] IP: zap_pte_range (mm/memory.c:1132)
> Weird, I don't think we've seen anything like that before, have we?
> I'm pretty sure it's not a consequence of my "index = min(index, end)",
> but what it portends I don't know.  Please confirm mm/memory.c:1132 -
> that's the "if (PageAnon(page))" line, isn't it?  Which indeed matches
> the code below.  So accessing page->mapping is causing an oops...

Right, that's the correct line.

At this point I'm pretty sure that it's somehow related to that one line
patch since it reproduced fairly quickly after applying it, and when I
removed it I didn't see it happening again during the overnight fuzzing.


Thanks,
Sasha

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