REISERFS (device loop0): Using r5 hash to sort names
reiserfs: enabling write barrier flush mode
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.4.0-syzkaller-00082-gc0a572d9d32f #0 Not tainted
------------------------------------------------------
syz-executor412/5000 is trying to acquire lock:
ffff888014ee3090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0x100 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff888076eb82e0 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:813 [inline]
ffff888076eb82e0 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: do_unlinkat+0x280/0x680 fs/namei.c:4380

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}:
       down_write_nested+0x96/0x200 kernel/locking/rwsem.c:1689
       inode_lock_nested include/linux/fs.h:813 [inline]
       do_unlinkat+0x280/0x680 fs/namei.c:4380
       __do_sys_unlinkat fs/namei.c:4438 [inline]
       __se_sys_unlinkat fs/namei.c:4431 [inline]
       __x64_sys_unlinkat+0xc1/0x130 fs/namei.c:4431
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (sb_writers#9){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1503 [inline]
       sb_start_write include/linux/fs.h:1578 [inline]
       mnt_want_write_file+0x98/0x5d0 fs/namespace.c:447
       reiserfs_ioctl+0x1a8/0x330 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl fs/ioctl.c:856 [inline]
       __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&sbi->lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3113 [inline]
       check_prevs_add kernel/locking/lockdep.c:3232 [inline]
       validate_chain kernel/locking/lockdep.c:3847 [inline]
       __lock_acquire+0x2fcd/0x5f30 kernel/locking/lockdep.c:5088
       lock_acquire kernel/locking/lockdep.c:5705 [inline]
       lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5670
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
       reiserfs_write_lock+0x79/0x100 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x175/0x610 fs/reiserfs/namei.c:364
       lookup_one_qstr_excl+0x11b/0x180 fs/namei.c:1605
       do_unlinkat+0x298/0x680 fs/namei.c:4381
       __do_sys_unlinkat fs/namei.c:4438 [inline]
       __se_sys_unlinkat fs/namei.c:4431 [inline]
       __x64_sys_unlinkat+0xc1/0x130 fs/namei.c:4431
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  &sbi->lock --> sb_writers#9 --> &type->i_mutex_dir_key#6/1

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&type->i_mutex_dir_key#6/1);
                               lock(sb_writers#9);
                               lock(&type->i_mutex_dir_key#6/1);
  lock(&sbi->lock);

 *** DEADLOCK ***

2 locks held by syz-executor412/5000:
 #0: ffff888078e96460 (sb_writers#9){.+.+}-{0:0}, at: do_unlinkat+0x190/0x680 fs/namei.c:4376
 #1: ffff888076eb82e0 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:813 [inline]
 #1: ffff888076eb82e0 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: do_unlinkat+0x280/0x680 fs/namei.c:4380

stack backtrace:
CPU: 1 PID: 5000 Comm: syz-executor412 Not tainted 6.4.0-syzkaller-00082-gc0a572d9d32f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2188
 check_prev_add kernel/locking/lockdep.c:3113 [inline]
 check_prevs_add kernel/locking/lockdep.c:3232 [inline]
 validate_chain kernel/locking/lockdep.c:3847 [inline]
 __lock_acquire+0x2fcd/0x5f30 kernel/locking/lockdep.c:5088
 lock_acquire kernel/locking/lockdep.c:5705 [inline]
 lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5670
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
 reiserfs_write_lock+0x79/0x100 fs/reiserfs/lock.c:27
 reiserfs_lookup+0x175/0x610 fs/reiserfs/namei.c:364
 lookup_one_qstr_excl+0x11b/0x180 fs/namei.c:1605
 do_unlinkat+0x298/0x680 fs/namei.c:4381
 __do_sys_unlinkat fs/namei.c:4438 [inline]
 __se_sys_unlinkat fs/namei.c:4431 [inline]
 __x64_sys_unlinkat+0xc1/0x130 fs/namei.c:4431
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f75938028f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe67d53328 EFLAGS: 00000246 ORIG_RAX: 0000000000000107