syzbot

REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.7.0-rc7-syzkaller-00016-gf5837722ffec #0 Not tainted
------------------------------------------------------
syz-executor403/5055 is trying to acquire lock:
ffff8880775782e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:802 [inline]
ffff8880775782e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: vfs_setxattr+0x1e1/0x420 fs/xattr.c:321

but task is already holding lock:
ffff88801de20418 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:404

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#9){.+.+}-{0:0}:
       lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1635 [inline]
       sb_start_write+0x4d/0x1c0 include/linux/fs.h:1710
       mnt_want_write_file+0x61/0x200 fs/namespace.c:448
       reiserfs_ioctl+0x178/0x2f0 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:871 [inline]
       __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:857
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

-> #1 (&sbi->lock){+.+.}-{3:3}:
       lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x136/0xd60 kernel/locking/mutex.c:747
       reiserfs_write_lock+0x7a/0xd0 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x162/0x580 fs/reiserfs/namei.c:364
       __lookup_slow+0x282/0x3e0 fs/namei.c:1694
       lookup_one_len+0x188/0x2c0 fs/namei.c:2746
       reiserfs_lookup_privroot+0x89/0x180 fs/reiserfs/xattr.c:977
       reiserfs_fill_super+0x21c1/0x2620 fs/reiserfs/super.c:2174
       mount_bdev+0x237/0x300 fs/super.c:1650
       legacy_get_tree+0xef/0x190 fs/fs_context.c:662
       vfs_get_tree+0x8c/0x2a0 fs/super.c:1771
       do_new_mount+0x28f/0xae0 fs/namespace.c:3337
       do_mount fs/namespace.c:3677 [inline]
       __do_sys_mount fs/namespace.c:3886 [inline]
       __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3863
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

-> #0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain+0x1909/0x5ab0 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
       inode_lock include/linux/fs.h:802 [inline]
       vfs_setxattr+0x1e1/0x420 fs/xattr.c:321
       do_setxattr fs/xattr.c:630 [inline]
       setxattr+0x25d/0x2f0 fs/xattr.c:653
       path_setxattr+0x1c0/0x2a0 fs/xattr.c:672
       __do_sys_setxattr fs/xattr.c:688 [inline]
       __se_sys_setxattr fs/xattr.c:684 [inline]
       __x64_sys_setxattr+0xbb/0xd0 fs/xattr.c:684
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#6 --> &sbi->lock --> sb_writers#9

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_writers#9);
                               lock(&sbi->lock);
                               lock(sb_writers#9);
  lock(&type->i_mutex_dir_key#6);

 *** DEADLOCK ***

1 lock held by syz-executor403/5055:
 #0: ffff88801de20418 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:404

stack backtrace:
CPU: 0 PID: 5055 Comm: syz-executor403 Not tainted 6.7.0-rc7-syzkaller-00016-gf5837722ffec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x366/0x490 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain+0x1909/0x5ab0 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
 down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
 inode_lock include/linux/fs.h:802 [inline]
 vfs_setxattr+0x1e1/0x420 fs/xattr.c:321
 do_setxattr fs/xattr.c:630 [inline]
 setxattr+0x25d/0x2f0 fs/xattr.c:653
 path_setxattr+0x1c0/0x2a0 fs/xattr.c:672
 __do_sys_setxattr fs/xattr.c:688 [inline]
 __se_sys_setxattr fs/xattr.c:684 [inline]
 __x64_sys_setxattr+0xbb/0xd0 fs/xattr.c:684
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fc8872e8609
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd42cfbb68 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007ffd42cfbd38 RCX: 00007fc8872e8609
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000020000080
RBP: 00007fc88735c610 R08: 0000000000000001 R09: 00007ffd42cfbd38
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007