diff options
| author | Jan Kara <jack@suse.cz> | 2017-03-02 16:50:13 +0100 |
|---|---|---|
| committer | Ritesh Harjani <riteshh@codeaurora.org> | 2017-10-18 12:05:44 +0530 |
| commit | 16d289189c40a69737bbb59ea6520ab4dec205da (patch) | |
| tree | edf35c568a7700c1018447bf7617ee6009db79d6 | |
| parent | 9c197e78d2888e51936f5794ae9356ef42aca160 (diff) | |
block: Initialize bd_bdi on inode initialization
So far we initialized bd_bdi only in bdget(). That is fine for normal
bdev inodes however for the special case of the root inode of
blockdev_superblock that function is never called and thus bd_bdi is
left uninitialized. As a result bdev_evict_inode() may oops doing
bdi_put(root->bd_bdi) on that inode as can be seen when doing:
mount -t bdev none /mnt
Fix the problem by initializing bd_bdi when first allocating the inode
and then reinitializing bd_bdi in bdev_evict_inode().
Thanks to syzkaller team for finding the problem.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: b1d2dc5659b4 ("block: Make blk_get_backing_dev_info() safe without open bdev")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Change-Id: I9c34ca321ab311936946187ed21e25d67caf5ba5
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
Git-commit: 7ee143f46cb1f58ee07194076b9a3e6ea3f27ad3
[riteshh@codeaurora.org: resolved merge conflicts]
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
| -rw-r--r-- | fs/block_dev.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 49533c903467..d3c296d4eb25 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -532,6 +532,7 @@ static void init_once(void *foo) #ifdef CONFIG_SYSFS INIT_LIST_HEAD(&bdev->bd_holder_disks); #endif + bdev->bd_bdi = &noop_backing_dev_info; inode_init_once(&ei->vfs_inode); /* Initialize mutex for freeze. */ mutex_init(&bdev->bd_fsfreeze_mutex); @@ -557,8 +558,10 @@ static void bdev_evict_inode(struct inode *inode) } list_del_init(&bdev->bd_list); spin_unlock(&bdev_lock); - if (bdev->bd_bdi != &noop_backing_dev_info) + if (bdev->bd_bdi != &noop_backing_dev_info) { bdi_put(bdev->bd_bdi); + bdev->bd_bdi = &noop_backing_dev_info; + } } static const struct super_operations bdev_sops = { @@ -657,7 +660,6 @@ struct block_device *bdget(dev_t dev) bdev->bd_contains = NULL; bdev->bd_super = NULL; bdev->bd_inode = inode; - bdev->bd_bdi = &noop_backing_dev_info; bdev->bd_block_size = (1 << inode->i_blkbits); bdev->bd_part_count = 0; bdev->bd_invalidated = 0; |