On Wed, Dec 04, 2024 at 11:21:53AM +0800, Lai, Yi wrote: > On Wed, Oct 30, 2024 at 07:08:48PM +0800, Ming Lei wrote: > > 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/ > > > > > For v6.13-rc3, there is possible deadlock in > blk_trace_ioctl/perf_event_ctx_lock_nested/in blk_trace_ioctl. Based on > my bisection log, it all bisected to your commit f1be1788a32e block: > model freeze & enter queue as lock for supporting lockdep. > > I am hoping this will be insightful to you. > > possible deadlock in blk_trace_ioctl: > [ 33.317360] ffff88800fc8f3e0 (&mm->mmap_lock){++++}-{4:4}, at: __might_fault+0xf1/0x1b0 > [ 33.317859] > [ 33.317859] but task is already holding lock: > [ 33.318206] ffff8880109b92e0 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_ioctl+0xaa/0x290 > [ 33.318722] > [ 33.318722] which lock already depends on the new lock. > [ 33.318722] The warning has been fixed by the following patches in for-6.14/block: blktrace: move copy_[to|from]_user() out of ->debugfs_lock blktrace: don't centralize grabbing q->debugfs_mutex in blk_trace_ioctl https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/log/?h=for-6.14/block Thanks, Ming
