REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using r5 hash to sort names
REISERFS (device loop0): using 3.5.x disk format
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.6.0-rc4-syzkaller-00284-gb9ddbb0cde2a #0 Not tainted
------------------------------------------------------
syz-executor504/5029 is trying to acquire lock:
ffff8880203e8410 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write_file+0x61/0x200 fs/namespace.c:447

but task is already holding lock:
ffff88814074a090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7a/0xd0 fs/reiserfs/lock.c:27

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&sbi->lock){+.+.}-{3:3}:
       __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:1693
       lookup_one_len+0x18b/0x2d0 fs/namei.c:2745
       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:1629
       legacy_get_tree+0xef/0x190 fs/fs_context.c:638
       vfs_get_tree+0x8c/0x280 fs/super.c:1750
       do_new_mount+0x28f/0xae0 fs/namespace.c:3335
       do_mount fs/namespace.c:3675 [inline]
       __do_sys_mount fs/namespace.c:3884 [inline]
       __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3861
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&type->i_mutex_dir_key#6){+.+.}-{3:3}:
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:802 [inline]
       open_last_lookups fs/namei.c:3560 [inline]
       path_openat+0x7c2/0x3180 fs/namei.c:3793
       do_filp_open+0x234/0x490 fs/namei.c:3823
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1422
       do_sys_open fs/open.c:1437 [inline]
       __do_sys_openat fs/open.c:1453 [inline]
       __se_sys_openat fs/open.c:1448 [inline]
       __x64_sys_openat+0x247/0x290 fs/open.c:1448
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sb_writers#9){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3868 [inline]
       __lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5136
       lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1571 [inline]
       sb_start_write+0x4d/0x1c0 include/linux/fs.h:1646
       mnt_want_write_file+0x61/0x200 fs/namespace.c:447
       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:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by syz-executor504/5029:
 #0: ffff88814074a090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7a/0xd0 fs/reiserfs/lock.c:27

stack backtrace:
CPU: 1 PID: 5029 Comm: syz-executor504 Not tainted 6.6.0-rc4-syzkaller-00284-gb9ddbb0cde2a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x375/0x4a0 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 kernel/locking/lockdep.c:3868 [inline]
 __lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5136
 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1571 [inline]
 sb_start_write+0x4d/0x1c0 include/linux/fs.h:1646
 mnt_want_write_file+0x61/0x200 fs/namespace.c:447
 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:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fca61b1b639
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:00007ffed91ca878 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffff