From f61033390bc34cd22ad4b4c12619a1e7a8a75600 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 17 Oct 2023 20:48:22 +0200 Subject: [PATCH] block: assert that we're not holding open_mutex over blk_report_disk_dead blk_report_disk_dead() has the following major callers: (1) del_gendisk() (2) blk_mark_disk_dead() Since del_gendisk() acquires disk->open_mutex it's clear that all callers are assumed to be called without disk->open_mutex held. In turn, blk_report_disk_dead() is called without disk->open_mutex held in del_gendisk(). All callers of blk_mark_disk_dead() call it without disk->open_mutex as well. Ensure that it is clear that blk_report_disk_dead() is called without disk->open_mutex on purpose by asserting it and a comment in the code. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231017184823.1383356-5-hch@lst.de Reviewed-by: Ming Lei Reviewed-by: Jan Kara Reviewed-by: Jens Axboe Signed-off-by: Christian Brauner --- block/genhd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/block/genhd.c b/block/genhd.c index 4a16a424f57d..c9d06f72c587 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -559,6 +559,13 @@ static void blk_report_disk_dead(struct gendisk *disk, bool surprise) struct block_device *bdev; unsigned long idx; + /* + * On surprise disk removal, bdev_mark_dead() may call into file + * systems below. Make it clear that we're expecting to not hold + * disk->open_mutex. + */ + lockdep_assert_not_held(&disk->open_mutex); + rcu_read_lock(); xa_for_each(&disk->part_tbl, idx, bdev) { if (!kobject_get_unless_zero(&bdev->bd_device.kobj)) -- 2.39.5