Re: INFO: possible circular locking dependency detected 3.1.0-rc2-00190-g3210d19

[Josh Boyer]

On Mon, Aug 22, 2011 at 9:16 AM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Mon, Aug 22, 2011 at 09:09:14AM -0400, Josh Boyer wrote:
>
>> We've had a report of this on 3.0.1 as well.  Slightly different
>> scenario and fs, but the locks in question are the same.
>> https://bugzilla.redhat.com/show_bug.cgi?id=730998
>>
>> It seems that with CONFIG_PROVE_LOCKING on, might_fault will always
>> attempt to grab mm->mmap_sem.  The common flow here is that getdents
>> calls filldir, which calls copy_to_user, which is what is calling
>> might_fault.
>>
>> Beyond that, I'm a bit over my head at the moment because I don't know
>> if the VFS is right and we just need some more lockdep annotations or
>> if there really is a problem.
>
> Don't grab ->i_mutex in ->evict_inode().  Why are you doing that, anyway?

I've no idea.  Let's ask Ted!

josh
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