On Fri, Feb 21, 2025 at 5:30 PM Keith Busch <kbusch@xxxxxxxxxx> wrote: > This patch appears to be triggering a new warning in certain conditions > when tearing down an nvme namespace's block device. Stack trace is at > the end. > > The warning indicates that this shouldn't be called from a > WQ_MEM_RECLAIM workqueue. This workqueue is responsible for bringing up > and tearing down block devices, so this is a memory reclaim use AIUI. > I'm a bit confused why we can't tear down a disk from within a memory > reclaim workqueue. Is the recommended solution to simply remove the WQ > flag when creating the workqueue? > This ends up calling into bioset_exit -> bio_put_slab -> kmem_cache_destroy Sizes of the bio- slabs are off the beaten path, so it may be they make sense to exist. With the assumption that caches should be there, this can instead invoke kmem_cache_destroy from a queue where it is safe to do it. This is not supposed to be a frequent operation. -- Mateusz Guzik <mjguzik gmail.com>
