linux/fs/f2fs
Chao Yu 5eaac835f2 f2fs: fix to avoid potential deadlock
There is a potential deadlock reported by syzbot as below:

F2FS-fs (loop2): invalid crc value
F2FS-fs (loop2): Found nat_bits in checkpoint
F2FS-fs (loop2): Mounted with checkpoint version = 48b305e4
======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc8-syzkaller-33330-ga5541c0811a0 #0 Not tainted
------------------------------------------------------
syz-executor.2/32123 is trying to acquire lock:
ffff0000c0e1a608 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x54/0xb4 mm/memory.c:5644

but task is already holding lock:
ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2205 [inline]
ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: f2fs_ioc_get_encryption_pwsalt fs/f2fs/file.c:2334 [inline]
ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: __f2fs_ioctl+0x1370/0x3318 fs/f2fs/file.c:4151

which lock already depends on the new lock.

Chain exists of:
  &mm->mmap_lock --> &nm_i->nat_tree_lock --> &sbi->sb_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->sb_lock);
                               lock(&nm_i->nat_tree_lock);
                               lock(&sbi->sb_lock);
  lock(&mm->mmap_lock);

Let's try to avoid above deadlock condition by moving __might_fault()
out of sbi->sb_lock coverage.

Fixes: 95fa90c9e5 ("f2fs: support recording errors into superblock")
Link: https://lore.kernel.org/linux-f2fs-devel/000000000000cd5fe305ef617fe2@google.com/T/#u
Reported-by: syzbot+4793f6096d174c90b4f7@syzkaller.appspotmail.com
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2023-01-06 15:13:41 -08:00
..
acl.c fs: pass dentry to set acl method 2022-10-19 12:55:42 +02:00
acl.h fs: pass dentry to set acl method 2022-10-19 12:55:42 +02:00
checkpoint.c f2fs: fix return val in f2fs_start_ckpt_thread() 2022-11-01 17:56:04 -07:00
compress.c f2fs: split __submit_bio 2023-01-06 15:12:56 -08:00
data.c f2fs: introduce IS_F2FS_IPU_* macro 2023-01-06 15:13:41 -08:00
debug.c f2fs: fix some format WARNING in debug.c and sysfs.c 2022-12-12 14:59:39 -08:00
dir.c f2fs: change type for 'sbi->readdir_ra' 2022-11-28 12:46:33 -08:00
extent_cache.c f2fs: add a f2fs_lookup_extent_cache_block helper 2023-01-06 15:13:00 -08:00
f2fs.h f2fs: remove the create argument to f2fs_map_blocks 2023-01-06 15:13:29 -08:00
file.c f2fs: fix to avoid potential deadlock 2023-01-06 15:13:41 -08:00
gc.c f2fs: add a f2fs_lookup_extent_cache_block helper 2023-01-06 15:13:00 -08:00
gc.h f2fs: remove redundant code for gc condition 2022-07-30 20:16:20 -07:00
hash.c f2fs: don't use casefolded comparison for "." and ".." 2022-05-17 11:19:23 -07:00
inline.c f2fs: support recording errors into superblock 2022-10-04 13:31:45 -07:00
inode.c f2fs: add block_age-based extent cache 2022-12-12 14:53:56 -08:00
iostat.c f2fs: iostat: support accounting compressed IO 2022-08-29 21:15:51 -07:00
iostat.h f2fs: iostat: support accounting compressed IO 2022-08-29 21:15:51 -07:00
Kconfig
Makefile
namei.c f2fs-for-6.2-rc1 2022-12-14 15:27:57 -08:00
node.c f2fs: add block_age-based extent cache 2022-12-12 14:53:56 -08:00
node.h f2fs: add block_age-based extent cache 2022-12-12 14:53:56 -08:00
recovery.c f2fs: do some cleanup for f2fs module init 2022-12-08 09:32:20 -08:00
segment.c f2fs: introduce IS_F2FS_IPU_* macro 2023-01-06 15:13:41 -08:00
segment.h f2fs: introduce IS_F2FS_IPU_* macro 2023-01-06 15:13:41 -08:00
shrinker.c f2fs: add block_age-based extent cache 2022-12-12 14:53:56 -08:00
super.c f2fs: introduce IS_F2FS_IPU_* macro 2023-01-06 15:13:41 -08:00
sysfs.c f2fs: fix some format WARNING in debug.c and sysfs.c 2022-12-12 14:59:39 -08:00
verity.c - Alistair Popple has a series which addresses a race which causes page 2022-10-14 12:28:43 -07:00
xattr.c f2fs: support recording errors into superblock 2022-10-04 13:31:45 -07:00
xattr.h