Re: CVE-2025-40146: blk-mq: fix potential deadlock while nr_requests grown

[Greg KH]

On Thu, Nov 27, 2025 at 09:22:42PM +0800, Zheng Qixing wrote:
> Hi,
> 
> Commit b86433721f46 ("blk-mq: fix potential deadlock while nr_requests
> grown")  aims to avoid a deadlock issue when the queue is frozen and memory
> reclaim is triggered.
> 
> However, the sysfs nr_requests update path is already under a
> memalloc_noio_save() region while the queue is frozen (via
> blk_mq_freeze_queue()).

Did the lockdep splat in
https://lore.kernel.org/all/0659ea8d-a463-47c8-9180-43c719e106eb@xxxxxxxxxxxxx/
not describe the issue here that the commit is attempting to solve?

thanks,

greg k-h