Re: [PATCH] block: fix module reference leak in mq-deadline I/O scheduler

[Hannes Reinecke <hare@suse.de>]

On 7/19/25 15:26, Nilay Shroff wrote:
> During probe, when the block layer registers a request queue, it
> defaults to the mq-deadline I/O scheduler if the device is single-queue
> and the mq-deadline module is available. To determine availability, the
> elevator_set_default() invokes elevator_find_get(), which increments the
> module's reference count. However, this reference is never released,
> resulting in a module reference leak that prevents the mq-deadline module
> from being unloaded.
> 
> This patch fixes the issue by ensuring the acquired module reference is
> properly released.
> 
> Fixes: 1e44bedbc921 ("block: unifying elevator change")
> Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
> ---
> Note: This patch is based on https://lore.kernel.org/all/20250718133232.626418-1-nilay@linux.ibm.com/
> So please apply this patch after the above is merged.
> ---
>   block/elevator.c | 19 +++++++++++++------
>   1 file changed, 13 insertions(+), 6 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
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