From: Ming Lei Date: Mon, 13 Jan 2025 01:58:33 +0000 (+0800) Subject: block: mark GFP_NOIO around sysfs ->store() X-Git-Tag: v6.14-rc1~202^2~14 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7c0be4ead1f8f5f8be0803f347de0de81e3b8e1c;p=thirdparty%2Fkernel%2Flinux.git block: mark GFP_NOIO around sysfs ->store() 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 Cc: stable@vger.kernel.org Signed-off-by: Ming Lei Reviewed-by: Christoph Hellwig Reviewed-by: John Garry Link: https://lore.kernel.org/r/20250113015833.698458-1-ming.lei@redhat.com Link: https://lore.kernel.org/linux-block/Z4RkemI9f6N5zoEF@fedora/T/#mc774c65eeca5c024d29695f9ac6152b87763f305 Signed-off-by: Jens Axboe --- diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index e828be777206b..e09b455874bfd 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -681,6 +681,7 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr, 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, struct attribute *attr, 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;