Re: [Bug #15805] reiserfs locking

Frederic Weisbecker
2010-04-22T02:52:27Z

On Tue, Apr 20, 2010 at 05:19:25AM +0200, Rafael J. Wysocki wrote:
> This message has been generated automatically as a part of a summary report
> of recent regressions.
>
> The following bug entry is on the current list of known regressions
> from 2.6.33. Please verify if it still should be listed and let the tracking team
> know (either way).
>
>
> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=15805
> Subject : reiserfs locking
> Submitter : Alexander Beregalov <a.beregalov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Date : 2010-04-15 21:02 (5 days old)
> Message-ID : <t2ka4423d671004151402n7b2dc425mdc9c6bb9640d63fb-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
> References : http://marc.info/?l=linux-kernel&m=127136535323933&w=2

That doesn't look like related to the bkl removal.

In fact what I wonder is how we missed that before.

vfs_readdir() take the directory inode mutex
|
------- copy_to_user() takes the mm->mmap_sem

sys_unmap() takes mm->mmap_sem
|
------- reiserfs_file_release() takes inode mutex

The lock inversion can not happen as sys_getdents() can't be called
after the directory is closed.

I'm not sure what to do. Adding more people in Cc.