[PATCH 01/10] block: delay freeing the gendisk

[Christoph Hellwig <hch@lst.de>]

blkdev_get_no_open acquires a reference to the block_device through
the block device inode and then tries to acquire a device model
reference to the gendisk.  But at this point the disk migh already
be freed (although the race is free).  Fix this by only freeing the
gendisk from the whole device bdevs ->free_inode callback as well.

Fixes: 22ae8ce8b892 ("block: simplify bdev/disk lookup in blkdev_get")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
---
 block/genhd.c  | 3 +--
 fs/block_dev.c | 2 ++
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index af4d2ab4a633..298ee78c1bda 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1079,10 +1079,9 @@ static void disk_release(struct device *dev)
 	disk_release_events(disk);
 	kfree(disk->random);
 	xa_destroy(&disk->part_tbl);
-	bdput(disk->part0);
 	if (test_bit(GD_QUEUE_REF, &disk->state) && disk->queue)
 		blk_put_queue(disk->queue);
-	kfree(disk);
+	bdput(disk->part0);	/* frees the disk */
 }
 struct class block_class = {
 	.name		= "block",
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0c424a0cadaa..9ef4f1fc2cb0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -812,6 +812,8 @@ static void bdev_free_inode(struct inode *inode)
 	free_percpu(bdev->bd_stats);
 	kfree(bdev->bd_meta_info);
 
+	if (!bdev_is_partition(bdev))
+		kfree(bdev->bd_disk);
 	kmem_cache_free(bdev_cachep, BDEV_I(inode));
 }
 
-- 
2.30.2