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block: mark GFP_NOIO around sysfs ->store()

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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@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John 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: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2025-01-13 09:58:33 +08:00 committed by Jens Axboe
parent 9752b55035
commit 7c0be4ead1
1 changed files with 3 additions and 0 deletions
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3
block/blk-sysfs.c
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@ -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;