6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei <tom.leiming@xxxxxxxxx> commit 7c0be4ead1f8f5f8be0803f347de0de81e3b8e1c upstream. 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() Reported-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx> Link: https://lore.kernel.org/r/20250113015833.698458-1-ming.lei@xxxxxxxxxx Link: https://lore.kernel.org/linux-block/Z4RkemI9f6N5zoEF@fedora/T/#mc774c65eeca5c024d29695f9ac6152b87763f305 Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- block/blk-sysfs.c | 3 +++ 1 file changed, 3 insertions(+) --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -681,6 +681,7 @@ queue_attr_store(struct kobject *kobj, s struct queue_sysfs_entry *entry = to_queue(attr); struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj); struct request_queue *q = disk->queue; + unsigned int noio_flag; ssize_t res; if (!entry->store_limit && !entry->store) @@ -711,7 +712,9 @@ queue_attr_store(struct kobject *kobj, s mutex_lock(&q->sysfs_lock); blk_mq_freeze_queue(q); + noio_flag = memalloc_noio_save(); res = entry->store(disk, page, length); + memalloc_noio_restore(noio_flag); blk_mq_unfreeze_queue(q); mutex_unlock(&q->sysfs_lock); return res;
