Re: [PATCH V2] block: mark GFP_NOIO around sysfs ->store()

Hi!

On Mon, 2025-01-13 at 16:41 +0800, Ming Lei wrote:

sysfs ->store is called with queue freezed, meantime we have several ->store() callbacks(update_nr_requests, wbt, scheduler) to allocate memory with GFP_KERNEL which may run into direct reclaim code path, then potential deadlock can be caused.

Fix the issue by marking NOIO around sysfs ->store()

Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: John Garry john.g.garry@oracle.com Reported-by: Thomas Hellström thomas.hellstrom@linux.intel.com Closes: https://lore.kernel.org/linux-block/ead7c5ce5138912c1f3179d62370b84a64014a38... Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers")

Does this fix also the #2 lockdep splat in that email? Thanks,

Thomas