Commit 8ea00501 authored by Ming Lei's avatar Ming Lei Committed by Li Lingfeng
Browse files

block: mark GFP_NOIO around sysfs ->store() 

mainline inclusion
from mainline-v6.14-rc1
commit 7c0be4ead1f8f5f8be0803f347de0de81e3b8e1c
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPLKB
CVE: CVE-2025-21817

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c0be4ead1f8f5f8be0803f347de0de81e3b8e1c



--------------------------------

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: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohn Garry <john.g.garry@oracle.com>
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: default avatarJens Axboe <axboe@kernel.dk>
Conflicts:
  block/blk-sysfs.c
[Commit a16230649ce27f8ac7dd8a5b079d9657aa96de16 ("block: add a
store_limit operations for sysfs entries") add check of store_limit in
queue_attr_store;
commit af2814149883 ("block: freeze the queue in queue_attr_store") move
blk_mq_freeze_queue to queue_attr_store.]
Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
parent 9d22d5b7

block/blk-sysfs.c

+3 −0
Original line number Diff line number Diff line
@@ -773,13 +773,16 @@ 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)

		return -EIO;



	mutex_lock(&q->sysfs_lock);

	noio_flag = memalloc_noio_save();

	res = entry->store(q, page, length);

	memalloc_noio_restore(noio_flag);

	mutex_unlock(&q->sysfs_lock);

	return res;

}