diff options
| author | Ming Lei <ming.lei@redhat.com> | 2021-11-11 10:03:43 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-11-22 18:35:37 -0700 |
| commit | efcf5932230b9472cfdbe01c858726f29ac5ec7d (patch) | |
| tree | 81ebb94de5787993097f25294aa62fb3f426e22d /block | |
| parent | 2b504bd4841bccbf3eb83c1fec229b65956ad8ad (diff) | |
block: avoid to touch unloaded module instance when opening bdev
disk->fops->owner is grabbed in blkdev_get_no_open() after the disk
kobject refcount is increased. This way can't make sure that
disk->fops->owner is still alive since del_gendisk() still can move
on if the kobject refcount of disk is grabbed by open() and
disk->fops->open() isn't called yet.
Fixes the issue by moving try_module_get() into blkdev_get_by_dev()
with ->open_mutex() held, then we can drain the in-progress open()
in del_gendisk(). Meantime new open() won't succeed because disk
becomes not alive.
This way is reasonable because blkdev_get_no_open() needn't to touch
disk->fops or defined callbacks.
Cc: Christoph Hellwig <hch@lst.de>
Cc: czhong@redhat.com
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211111020343.316126-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/bdev.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/block/bdev.c b/block/bdev.c index b4dab2fb6a74..b1d087e5e205 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -753,8 +753,7 @@ struct block_device *blkdev_get_no_open(dev_t dev) if (!bdev) return NULL; - if ((bdev->bd_disk->flags & GENHD_FL_HIDDEN) || - !try_module_get(bdev->bd_disk->fops->owner)) { + if ((bdev->bd_disk->flags & GENHD_FL_HIDDEN)) { put_device(&bdev->bd_device); return NULL; } @@ -764,7 +763,6 @@ struct block_device *blkdev_get_no_open(dev_t dev) void blkdev_put_no_open(struct block_device *bdev) { - module_put(bdev->bd_disk->fops->owner); put_device(&bdev->bd_device); } @@ -820,12 +818,14 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) ret = -ENXIO; if (!disk_live(disk)) goto abort_claiming; + if (!try_module_get(disk->fops->owner)) + goto abort_claiming; if (bdev_is_partition(bdev)) ret = blkdev_get_part(bdev, mode); else ret = blkdev_get_whole(bdev, mode); if (ret) - goto abort_claiming; + goto put_module; if (mode & FMODE_EXCL) { bd_finish_claiming(bdev, holder); @@ -847,7 +847,8 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) if (unblock_events) disk_unblock_events(disk); return bdev; - +put_module: + module_put(disk->fops->owner); abort_claiming: if (mode & FMODE_EXCL) bd_abort_claiming(bdev, holder); @@ -956,6 +957,7 @@ void blkdev_put(struct block_device *bdev, fmode_t mode) blkdev_put_whole(bdev, mode); mutex_unlock(&disk->open_mutex); + module_put(disk->fops->owner); blkdev_put_no_open(bdev); } EXPORT_SYMBOL(blkdev_put); |