linux/fs
Tejun Heo 614a4e3773 writeback, cgroup: fix premature wb_put() in locked_inode_to_wb_and_lock_list()
locked_inode_to_wb_and_lock_list() wb_get()'s the wb associated with
the target inode, unlocks inode, locks the wb's list_lock and verifies
that the inode is still associated with the wb.  To prevent the wb
going away between dropping inode lock and acquiring list_lock, the wb
is pinned while inode lock is held.  The wb reference is put right
after acquiring list_lock citing that the wb won't be dereferenced
anymore.

This isn't true.  If the inode is still associated with the wb, the
inode has reference and it's safe to return the wb; however, if inode
has been switched, the wb still needs to be unlocked which is a
dereference and can lead to use-after-free if it it races with wb
destruction.

Fix it by putting the reference after releasing list_lock.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 87e1d789bf ("writeback: implement [locked_]inode_to_wb_and_lock_list()")
Cc: stable@vger.kernel.org # v4.2+
Tested-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-03-20 09:44:18 -06:00
..
9p wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
adfs fs/adfs/adfs.h: tidy up comments 2016-01-20 17:09:18 -08:00
affs affs_do_readpage_ofs(): just use kmap_atomic() around memcpy() 2016-02-20 00:15:51 -05:00
afs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
autofs4 autofs4: use pr_xxx() macros directly for logging 2016-03-15 16:55:16 -07:00
befs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
bfs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
btrfs Linux 4.5-rc7 2016-03-07 09:27:30 +01:00
cachefiles wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ceph ceph: initial CEPH_FEATURE_FS_FILE_LAYOUT_V2 support 2016-03-04 21:00:37 +01:00
cifs Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-03-17 11:22:54 -07:00
coda Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
configfs configfs: switch ->default groups to a linked list 2016-03-06 16:11:24 +01:00
cramfs don't put symlink bodies in pagecache into highmem 2015-12-08 22:41:36 -05:00
debugfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
devpts pty: make sure super_block is still valid in final /dev/tty close 2016-02-06 23:45:46 -08:00
dlm dlm for 4.6 2016-03-17 16:38:36 -07:00
ecryptfs eCryptfs: Use skcipher and shash 2016-01-27 20:36:18 +08:00
efivarfs efi: Make efivarfs entries immutable by default 2016-02-10 16:25:52 +00:00
efs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
exofs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
exportfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ext2 Performance improvements in SEEK_DATA and xattr scalability 2016-03-17 16:31:18 -07:00
ext4 Performance improvements in SEEK_DATA and xattr scalability 2016-03-17 16:31:18 -07:00
f2fs f2fs: Use skcipher 2016-01-27 20:35:55 +08:00
fat wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
freevxfs don't put symlink bodies in pagecache into highmem 2015-12-08 22:41:36 -05:00
fscache FS-Cache: Handle a write to the page immediately beyond the EOF marker 2015-11-11 02:11:02 -05:00
fuse wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
gfs2 GFS2: merge window 2016-03-17 16:51:32 -07:00
hfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
hfsplus wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
hostfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
hpfs hpfs: don't truncate the file when delete fails 2016-02-27 19:15:51 -05:00
hugetlbfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
isofs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
jbd2 jbd2: do not fail journal because of frozen_buffer allocation failure 2016-03-13 17:38:20 -04:00
jffs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-03-11 10:13:49 -08:00
jfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
kernfs kernfs: make kernfs_walk_ns() use kernfs_pr_cont_buf[] 2016-02-07 20:21:35 -08:00
lockd lockd: constify nlmsvc_binding structure 2016-01-07 10:10:50 -05:00
logfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
minix kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
ncpfs ncpfs: fix a braino in OOM handling in ncp_fill_cache() 2016-03-07 22:25:16 -05:00
nfs NFSv4.x/pnfs: Fix a race between layoutget and bulk recalls 2016-02-22 17:46:34 -05:00
nfs_common
nfsd nfsd: Use shash 2016-01-27 20:36:13 +08:00
nilfs2 wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
nls
notify fsnotify: turn fsnotify reaper thread into a workqueue job 2016-02-18 16:23:24 -08:00
ntfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ocfs2 Configfs changes for the 4.6 merge window: 2016-03-17 16:25:46 -07:00
omfs
openpromfs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
overlayfs ovl: copy new uid/gid into overlayfs runtime inode 2016-03-03 17:17:46 +01:00
proc proc: revert /proc/<pid>/maps [stack:TID] annotation 2016-02-03 08:28:43 -08:00
pstore pstore: Add support for 64 Bit address space 2016-03-10 09:43:36 -08:00
qnx4 kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
qnx6 kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
quota wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ramfs don't put symlink bodies in pagecache into highmem 2015-12-08 22:41:36 -05:00
reiserfs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
romfs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
squashfs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
sysfs platform/chrome: Branch for v4.4 2015-11-13 21:53:18 -08:00
sysv kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
tracefs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
ubifs wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
udf Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-01-23 12:24:56 -08:00
ufs kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
xfs mm: simplify lock_page_memcg() 2016-03-15 16:55:16 -07:00
aio.c
anon_inodes.c
attr.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
bad_inode.c fs/bad_inode.c: is_bad_inode can be boolean 2015-12-06 21:17:14 -05:00
binfmt_aout.c
binfmt_elf_fdpic.c libnvdimm for 4.4: 2015-11-10 12:07:22 -08:00
binfmt_elf.c mm: ASLR: use get_random_long() 2016-02-27 10:28:52 -08:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
binfmt_script.c
block_dev.c Merge branch 'for-4.6/core' of git://git.kernel.dk/linux-block 2016-03-18 16:43:11 -07:00
buffer.c mm: simplify lock_page_memcg() 2016-03-15 16:55:16 -07:00
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c Merge 4.5-rc4 into char-misc-next 2016-02-14 14:25:59 -08:00
compat.c saner calling conventions for copy_mount_options() 2016-01-04 10:28:32 -05:00
coredump.c fs/coredump: prevent "" / "." / ".." core path components 2016-01-20 17:09:18 -08:00
dax.c dax: check return value of dax_radix_entry() 2016-03-09 15:43:42 -08:00
dcache.c use ->d_seq to get coherency between ->d_inode and ->d_flags 2016-02-29 12:16:43 -05:00
dcookies.c
direct-io.c block: fix use-after-free in dio_bio_complete 2016-01-30 22:02:10 -07:00
drop_caches.c
eventfd.c Documentation: filesystem: Fix typo in fs/eventfd.c 2015-12-08 14:52:03 +01:00
eventpoll.c epoll: restrict EPOLLEXCLUSIVE to POLLIN and POLLOUT 2016-02-05 18:10:40 -08:00
exec.c vfs: define kernel_copy_file_from_fd() 2016-02-21 09:06:10 -05:00
fcntl.c fcntl: allow to set O_DIRECT flag on pipe 2016-01-09 02:55:37 -05:00
fhandle.c
file_table.c
file.c kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
filesystems.c find_filesystem(): simplify comparison 2016-01-19 12:02:23 -05:00
fs_pin.c
fs_struct.c
fs-writeback.c writeback, cgroup: fix premature wb_put() in locked_inode_to_wb_and_lock_list() 2016-03-20 09:44:18 -06:00
inode.c writeback: initialize inode members that track writeback history 2016-02-16 14:57:21 -07:00
internal.h Merge branch 'for-linus' into work.misc 2016-01-08 21:20:11 -05:00
ioctl.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
Kconfig dax: re-enable dax pmd mappings 2016-01-15 17:56:32 -08:00
Kconfig.binfmt
libfs.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
locks.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
Makefile mbcache2: rename to mbcache 2016-02-22 22:35:22 -05:00
mbcache.c mbcache: add reusable flag to cache entries 2016-02-22 22:44:04 -05:00
mount.h
mpage.c fs/mpage.c:mpage_readpages(): use lru_to_page() helper 2016-03-15 16:55:16 -07:00
namei.c do_last(): ELOOP failure exit should be done after leaving RCU mode 2016-02-27 19:37:37 -05:00
namespace.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
no-block.c
nsfs.c
open.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
pipe.c pipe: limit the per-user amount of pages allocated in pipes 2016-01-19 19:25:21 -05:00
pnode.c fs/pnode.c: treat zero mnt_group_id-s as unequal 2016-02-20 00:15:52 -05:00
pnode.h
posix_acl.c xattr handlers: Simplify list operation 2015-12-13 19:46:12 -05:00
proc_namespace.c vfs: show_vfsstat: remove redundant initialization and check of error code 2015-12-06 21:17:16 -05:00
read_write.c fs: return -EOPNOTSUPP if clone is not supported 2016-02-27 19:15:51 -05:00
readdir.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
select.c poll: plug an unused argument to do_poll 2016-01-06 08:26:52 -05:00
seq_file.c
signalfd.c
splice.c fs: __generic_file_splice_read retry lookup on AOP_TRUNCATED_PAGE 2016-01-09 02:55:35 -05:00
stack.c
stat.c fs/stat.c: drop the last new_valid_dev check 2016-01-16 11:17:23 -08:00
statfs.c
super.c writeback: flush inode cgroup wb switches instead of pinning super_block 2016-03-03 14:42:50 -07:00
sync.c
timerfd.c timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper 2016-01-17 11:13:55 +01:00
userfaultfd.c userfaultfd: don't block on the last VM updates at exit time 2016-03-02 09:03:18 -08:00
utimes.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
xattr.c xattr handlers: plug a lock leak in simple_xattr_list 2016-02-20 00:15:51 -05:00