On Sun, 08 Sep 2024 09:07:04 +0900, Damien Le Moal wrote:
> Commit af2814149883 ("block: freeze the queue in queue_attr_store")
> changed queue_attr_store() to always freeze a sysfs attribute queue
> before calling the attribute store() method, to ensure that no IOs are
> in-flight when an attribute value is being updated.
>
> However, this change created a potential deadlock situation for the
> scheduler queue attribute as changing the queue elevator with
> elv_iosched_store() can result in a call to request_module() if the user
> requested module is not already registered. If the file of the requested
> module is stored on the block device of the frozen queue, a deadlock
> will happen as the read operations triggered by request_module() will
> wait for the queue freeze to end.
>
> [...]
Applied, thanks!
[1/1] block: Prevent deadlocks when switching elevators
commit: 3c031b721c0ee1d6237719a6a9d7487ef757487b
Best regards,
--
Jens Axboe
