Re: [Update PATCH V3] md: don't unregister sync_thread with reconfig_mutex held

[Song Liu <song@kernel.org>]

On Wed, May 11, 2022 at 1:10 AM Guoqing Jiang <guoqing.jiang@linux.dev> wrote:
>
>
>
> On 5/11/22 2:02 AM, Song Liu wrote:
> > On Tue, May 10, 2022 at 5:35 AM Donald Buczek <buczek@molgen.mpg.de> wrote:
> >> On 5/10/22 2:09 PM, Guoqing Jiang wrote:
> >>>
> >>> On 5/10/22 8:01 PM, Donald Buczek wrote:
> >>>>> I guess v2 is the best at the moment. I pushed a slightly modified v2 to
> >>>>> md-next.
> >>>> I think, this can be used to get a double-free from md_unregister_thread.
> >>>>
> >>>> Please review
> >>>>
> >>>> https://lore.kernel.org/linux-raid/8312a154-14fb-6f07-0cf1-8c970187cc49@molgen.mpg.de/
> >>> That is supposed to be addressed by the second one, pls consider it too.
> >> Right, but this has not been pulled into md-next. I just wanted to note, that the current state of md-next has this problem.
>
> Thanks for reminder.
>
> >> If the other patch is taken, too, and works as intended, that would be solved.
> >>
> >>> [PATCH 2/2] md: protect md_unregister_thread from reentrancy
> > Good catch!
> >
> > Guoqing, current 2/2 doesn't apply cleanly. Could you please resend it on top of
> > md-next?
>
> Hmm, no issue from my side.
>
> ~/source/md> git am
> 0001-md-protect-md_unregister_thread-from-reentrancy.patch
> Applying: md: protect md_unregister_thread from reentrancy
>
> ~/source/md> git log --oneline |head -5
> dc7147a88766 md: protect md_unregister_thread from reentrancy
> 5a36c493dc82 md: don't unregister sync_thread with reconfig_mutex held
> 49c3b9266a71 block: null_blk: Improve device creation with configfs
> db060f54e0c5 block: null_blk: Cleanup messages
> b3a0a73e8a79 block: null_blk: Cleanup device creation and deletion
>
> Anyway, it is attached. I will rebase it to your latest tree if
> something gets wrong.

Applied to md-next. Thanks!

Song