linux/fs/btrfs
Liu Bo 876d2cf141 Btrfs: fix double free of fs root
I got this warning while mounting a btrfs image,

[ 3020.509606] ------------[ cut here ]------------
[ 3020.510107] WARNING: CPU: 3 PID: 5581 at lib/idr.c:1051 ida_remove+0xca/0x190
[ 3020.510853] ida_remove called for id=42 which is not allocated.
[ 3020.511466] Modules linked in:
[ 3020.511802] CPU: 3 PID: 5581 Comm: mount Not tainted 4.7.0-rc5+ #274
[ 3020.512438] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.2-20150714_191134- 04/01/2014
[ 3020.513385]  0000000000000286 0000000021295d86 ffff88006c66b8f0 ffffffff8182ba5a
[ 3020.514153]  0000000000000000 0000000000000009 ffff88006c66b930 ffffffff810e0ed7
[ 3020.514928]  0000041b00000000 ffffffff8289a8c0 ffff88007f437880 0000000000000000
[ 3020.515717] Call Trace:
[ 3020.515965]  [<ffffffff8182ba5a>] dump_stack+0xc9/0x13f
[ 3020.516487]  [<ffffffff810e0ed7>] __warn+0x147/0x160
[ 3020.517005]  [<ffffffff810e0f4f>] warn_slowpath_fmt+0x5f/0x80
[ 3020.517572]  [<ffffffff8182e6ca>] ida_remove+0xca/0x190
[ 3020.518075]  [<ffffffff813a2bcc>] free_anon_bdev+0x2c/0x60
[ 3020.518609]  [<ffffffff81657a9f>] free_fs_root+0x13f/0x160
[ 3020.519138]  [<ffffffff8165c679>] btrfs_get_fs_root+0x379/0x3d0
[ 3020.519710]  [<ffffffff81e6e975>] ? __mutex_unlock_slowpath+0x155/0x2c0
[ 3020.520366]  [<ffffffff816615b1>] open_ctree+0x2e91/0x3200
[ 3020.520965]  [<ffffffff8161ede2>] btrfs_mount+0x1322/0x15b0
[ 3020.521536]  [<ffffffff81e60e74>] ? kmemleak_alloc_percpu+0x44/0x170
[ 3020.522167]  [<ffffffff8115f5e1>] ? lockdep_init_map+0x61/0x210
[ 3020.522780]  [<ffffffff813a4f59>] mount_fs+0x49/0x2c0
[ 3020.523305]  [<ffffffff813d840c>] vfs_kern_mount+0xac/0x1b0
[ 3020.523872]  [<ffffffff8161dee1>] btrfs_mount+0x421/0x15b0
[ 3020.524402]  [<ffffffff81e60e74>] ? kmemleak_alloc_percpu+0x44/0x170
[ 3020.525045]  [<ffffffff8115f5e1>] ? lockdep_init_map+0x61/0x210
[ 3020.525657]  [<ffffffff8115f5e1>] ? lockdep_init_map+0x61/0x210
[ 3020.526289]  [<ffffffff813a4f59>] mount_fs+0x49/0x2c0
[ 3020.526803]  [<ffffffff813d840c>] vfs_kern_mount+0xac/0x1b0
[ 3020.527365]  [<ffffffff813dc27a>] do_mount+0x41a/0x1770
[ 3020.527899]  [<ffffffff812e800d>] ? strndup_user+0x6d/0xc0
[ 3020.528447]  [<ffffffff812e7f68>] ? memdup_user+0x78/0xb0
[ 3020.528987]  [<ffffffff813ddad0>] SyS_mount+0x150/0x160
[ 3020.529493]  [<ffffffff81e72b7c>] entry_SYSCALL_64_fastpath+0x1f/0xbd

It turns out that we free fs root twice, btrfs_init_fs_root() calls
free_anon_bdev(root->anon_dev) and later then btrfs_get_fs_root() cals
free_fs_root which does another free_anon_bdev() and it ends up with the
above warning.

Instead of reset root->anon_dev to 0 after free_anon_bdev(), we can let
btrfs_init_fs_root() return directly since its callers have already done
the free job by calling free_fs_root().

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-07-26 13:52:25 +02:00
..
tests Btrfs: fix error return code in btrfs_init_test_fs() 2016-06-23 10:44:39 -07:00
acl.c posix_acl: Inode acl caching fixes 2016-03-31 00:30:15 -04:00
async-thread.c btrfs: async-thread: Fix a use-after-free error for trace 2016-01-25 16:50:26 -08:00
async-thread.h btrfs: async_thread: Fix workqueue 'max_active' value when initializing 2015-08-31 11:46:40 -07:00
backref.c Merge branch 'cleanups-4.7' into for-chris-4.7-20160525 2016-05-25 22:51:03 +02:00
backref.h btrfs: cleanup, remove inode_item_info helper 2015-01-14 19:23:47 +01:00
btrfs_inode.h Merge branch 'cleanups-4.7' into for-chris-4.7-20160525 2016-05-25 22:51:03 +02:00
check-integrity.c btrfs: Use correct format specifier 2016-06-17 18:32:40 +02:00
check-integrity.h
compression.c btrfs: make find_workspace warn if there are no workspaces 2016-05-10 09:46:16 +02:00
compression.h btrfs: move btrfs_compression_type to compression.h 2016-03-11 17:12:46 +01:00
ctree.c Btrfs: error out if generic_bin_search get invalid arguments 2016-07-26 13:52:25 +02:00
ctree.h Btrfs: add tracepoints for flush events 2016-07-07 18:45:53 +02:00
delayed-inode.c Btrfs: change delayed reservation fallback behavior 2016-07-07 18:45:53 +02:00
delayed-inode.h Btrfs: fix ->iterate_shared() by upgrading i_rwsem for delayed nodes 2016-06-25 06:20:10 -07:00
delayed-ref.c btrfs: drop null testing before destroy functions 2016-02-18 11:46:03 +01:00
delayed-ref.h btrfs: fix string and comment grammatical issues and typos 2016-05-25 22:35:14 +02:00
dev-replace.c Merge branch 'cleanups-4.7' into for-chris-4.7-20160525 2016-05-25 22:51:03 +02:00
dev-replace.h btrfs: refactor btrfs_dev_replace_start for reuse 2016-04-28 10:59:13 +02:00
dir-item.c Btrfs: make xattr replace operations atomic 2014-11-20 17:20:07 -08:00
disk-io.c Btrfs: fix double free of fs root 2016-07-26 13:52:25 +02:00
disk-io.h Btrfs: self-tests: Support non-4k page size 2016-06-02 19:23:14 +02:00
export.c BTRFS: support NFSv2 export 2015-10-06 06:55:23 -07:00
export.h
extent_io.c Btrfs: fix error handling in map_private_extent_buffer 2016-06-23 10:44:40 -07:00
extent_io.h Btrfs: self-tests: Support non-4k page size 2016-06-02 19:23:14 +02:00
extent_map.c btrfs: fix string and comment grammatical issues and typos 2016-05-25 22:35:14 +02:00
extent_map.h btrfs: cleanup, stop casting for extent_map->lookup everywhere 2016-01-15 19:22:28 +01:00
extent-tree.c Btrfs: check inconsistence between chunk and block group 2016-07-26 13:52:25 +02:00
file-item.c btrfs: sink gfp parameter to set_extent_bits 2016-04-29 11:01:47 +02:00
file.c Btrfs: fix delalloc accounting after copy_from_user faults 2016-07-21 04:03:40 -07:00
free-space-cache.c Btrfs: self-tests: Support non-4k page size 2016-06-02 19:23:14 +02:00
free-space-cache.h btrfs: fix string and comment grammatical issues and typos 2016-05-25 22:35:14 +02:00
free-space-tree.c Revert "btrfs: synchronize incompat feature bits with sysfs files" 2016-01-29 08:19:37 -08:00
free-space-tree.h Btrfs: implement the free space B-tree 2015-12-17 12:16:47 -08:00
hash.c btrfs: advertise which crc32c implementation is being used at module load 2016-06-06 14:08:28 +02:00
hash.h btrfs: advertise which crc32c implementation is being used at module load 2016-06-06 14:08:28 +02:00
inode-item.c btrfs: rename btrfs_std_error to btrfs_handle_fs_error 2016-04-28 10:36:54 +02:00
inode-map.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
inode-map.h Btrfs: Initialize btrfs_root->highest_objectid when loading tree root and subvolume roots 2016-01-15 19:25:02 +01:00
inode.c Btrfs: fix callers of btrfs_block_rsv_migrate 2016-07-07 18:45:53 +02:00
ioctl.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-05-27 17:14:05 -07:00
Kconfig rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
locking.c btrfs: cleanup, remove stray return statements 2016-01-07 14:30:52 +01:00
locking.h btrfs: fix lockups from btrfs_clear_path_blocking 2014-11-19 10:34:35 -08:00
lzo.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
Makefile Btrfs: add free space tree sanity tests 2015-12-17 12:16:47 -08:00
math.h btrfs: cleanup 64bit/32bit divs, compile time constants 2015-03-03 17:23:57 +01:00
ordered-data.c btrfs: fix disk_i_size update bug when fallocate() fails 2016-06-23 10:44:41 -07:00
ordered-data.h Btrfs: fix race setting block group readonly during device replace 2016-05-30 12:58:21 +01:00
orphan.c
print-tree.c btrfs: teach print_leaf about temporary item subtypes 2016-02-11 16:15:43 +01:00
print-tree.h
props.c btrfs: move btrfs_compression_type to compression.h 2016-03-11 17:12:46 +01:00
props.h
qgroup.c btrfs: fix string and comment grammatical issues and typos 2016-05-25 22:35:14 +02:00
qgroup.h btrfs: qgroup: Check if qgroup reserved space leaked 2015-10-21 18:41:10 -07:00
raid56.c btrfs: fix string and comment grammatical issues and typos 2016-05-25 22:35:14 +02:00
raid56.h Btrfs: add RAID 5/6 BTRFS_RBIO_REBUILD_MISSING operation 2015-08-09 07:34:26 -07:00
rcu-string.h
reada.c Btrfs: fix race between readahead and device replace/removal 2016-05-30 12:58:18 +01:00
relocation.c Btrfs: use FLUSH_LIMIT for relocation in reserve_metadata_bytes 2016-07-07 18:45:53 +02:00
root-tree.c Merge branch 'cleanups-4.7' into for-chris-4.7-20160525 2016-05-25 22:51:03 +02:00
scrub.c Btrfs: fix race setting block group back to RW mode during device replace 2016-05-30 12:58:24 +01:00
send.c Merge branch 'cleanups-4.7' into for-chris-4.7-20160525 2016-05-25 22:51:03 +02:00
send.h Btrfs: use linux/sizes.h to represent constants 2016-01-07 14:38:02 +01:00
struct-funcs.c btrfs: fix string and comment grammatical issues and typos 2016-05-25 22:35:14 +02:00
super.c btrfs: avoid blocking open_ctree from cleaner_kthread 2016-06-17 18:32:40 +02:00
sysfs.c btrfs: add missing bytes_readonly attribute file in sysfs 2016-07-26 13:52:25 +02:00
sysfs.h btrfs: sysfs: introduce helper for syncing bits with sysfs files 2016-01-21 18:50:40 +01:00
transaction.c Btrfs: track transid for delayed ref flushing 2016-06-22 17:54:18 -07:00
transaction.h btrfs: account for non-CoW'd blocks in btrfs_abort_transaction 2016-06-17 18:32:40 +02:00
tree-defrag.c Btrfs: fix locking bugs when defragging leaves 2015-12-18 02:51:32 +00:00
tree-log.c Merge branch 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2016-06-18 05:57:59 -10:00
tree-log.h Btrfs: fix unreplayable log after snapshot delete + parent dir fsync 2016-03-01 08:23:25 -08:00
ulist.c btrfs: fix string and comment grammatical issues and typos 2016-05-25 22:35:14 +02:00
ulist.h btrfs: ulist: Add ulist_del() function. 2015-06-10 09:26:17 -07:00
uuid-tree.c Btrfs: make btrfs_search_forward return with nodes unlocked 2014-09-17 13:38:02 -07:00
volumes.c Merge branch 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2016-06-25 08:42:31 -07:00
volumes.h Merge branch 'foreign/jeffm/uapi' into for-chris-4.7-20160516 2016-05-16 15:46:29 +02:00
xattr.c switch xattr_handler->set() to passing dentry and inode separately 2016-05-27 15:39:43 -04:00
xattr.h btrfs: Switch to generic xattr handlers 2016-05-17 19:17:09 -04:00
zlib.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00