Re: [PATCH 5.13 000/800] 5.13.2-rc1 review

[Naresh Kamboju]

On Wed, 14 Jul 2021 at 19:22, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
>
> On Wed, 14 Jul 2021 at 19:01, Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> >

<trim>

> My two cents,
> While running ssuite long running stress testing we have noticed deadlock.
>
> > So if you drop that, all works well?  I'll go drop that from the queues
> > now.
>
> Let me drop that patch and test it again.
>
> Crash log,
>
> [ 1957.278399] ============================================
> [ 1957.283717] WARNING: possible recursive locking detected
> [ 1957.289031] 5.13.2-rc1 #1 Not tainted
> [ 1957.292703] --------------------------------------------
> [ 1957.298016] kworker/u8:7/236 is trying to acquire lock:
> [ 1957.303241] ffff8cc203f92c38 (&bfqd->lock){-.-.}-{2:2}, at:
> bfq_finish_requeue_request+0x55/0x500 [bfq]
> [ 1957.312643]
> [ 1957.312643] but task is already holding lock:
> [ 1957.318467] ffff8cc203f92c38 (&bfqd->lock){-.-.}-{2:2}, at:
> bfq_insert_requests+0x81/0x1750 [bfq]
> [ 1957.327334]
> [ 1957.327334] other info that might help us debug this:
> [ 1957.333852]  Possible unsafe locking scenario:
> [ 1957.333852]
> [ 1957.339762]        CPU0
> [ 1957.342206]        ----
> [ 1957.344651]   lock(&bfqd->lock);
> [ 1957.347873]   lock(&bfqd->lock);
> [ 1957.351097]
> [ 1957.351097]  *** DEADLOCK ***
> [ 1957.351097]

Also noticed on stable-rc 5.12.17-rc1.

> Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
>
> ref:
> https://lkft.validation.linaro.org/scheduler/job/3058868#L2922

ref:
https://lkft.validation.linaro.org/scheduler/job/3058423#L3125


- Naresh