Re: [PATCH V2 3/3] block: model freeze & enter queue as lock for supporting lockdep

[Ming Lei]

On Wed, Oct 30, 2024 at 06:39:13PM +0800, Lai, Yi wrote:
> On Wed, Oct 30, 2024 at 05:50:15PM +0800, Ming Lei wrote:
> > On Wed, Oct 30, 2024 at 4:51 PM Lai, Yi <yi1.lai@xxxxxxxxxxxxxxx> wrote:
> > >
> > > On Wed, Oct 30, 2024 at 03:13:09PM +0800, Ming Lei wrote:
> > > > On Wed, Oct 30, 2024 at 02:45:03PM +0800, Lai, Yi wrote:
> > ...
> > > >
> > > > It should be addressed by the following patch:
> > > >
> > > > https://lore.kernel.org/linux-block/ZyEGLdg744U_xBjp@fedora/
> > > >
> > >
> > > I have applied proposed fix patch on top of next-20241029. Issue can
> > > still be reproduced.
> > >
> > > It seems the dependency chain is different from Marek's log and mine.
> > 
> > Can you post the new log since q->q_usage_counter(io)->fs_reclaim from
> > blk_mq_init_sched is cut down by the patch?
> >
> 
> New possible deadlock log after patch applied:

This one looks like one real deadlock, any memory allocation with
q->sysfs_lock held has such risk.

There is another similar report related with queue sysfs store operation:

https://lore.kernel.org/linux-scsi/ZxG38G9BuFdBpBHZ@fedora/
 



Thanks,
Ming