syzbot

reiserfs: enabling write barrier flush mode
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.7.0-rc5-syzkaller-00270-g0e389834672c #0 Not tainted
------------------------------------------------------
syz-executor233/5063 is trying to acquire lock:
ffff8880759b49c0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:802 [inline]
ffff8880759b49c0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: open_last_lookups fs/namei.c:3543 [inline]
ffff8880759b49c0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: path_openat+0x8bd/0x2c50 fs/namei.c:3776

but task is already holding lock:
ffff888079afc418 (sb_writers#10){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3535 [inline]
ffff888079afc418 (sb_writers#10){.+.+}-{0:0}, at: path_openat+0x19f6/0x2c50 fs/namei.c:3776

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#10){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1635 [inline]
       sb_start_write include/linux/fs.h:1710 [inline]
       mnt_want_write_file+0x98/0x600 fs/namespace.c:448
       reiserfs_ioctl+0x194/0x2e0 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:871 [inline]
       __se_sys_ioctl fs/ioctl.c:857 [inline]
       __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

-> #1 (&sbi->lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:747
       reiserfs_write_lock+0x79/0x100 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x184/0x690 fs/reiserfs/namei.c:364
       __lookup_slow+0x24d/0x450 fs/namei.c:1694
       lookup_one_len+0x17d/0x1b0 fs/namei.c:2746
       reiserfs_lookup_privroot+0x94/0x200 fs/reiserfs/xattr.c:977
       reiserfs_fill_super+0x1ab6/0x3160 fs/reiserfs/super.c:2192
       mount_bdev+0x1f3/0x2e0 fs/super.c:1650
       legacy_get_tree+0x109/0x220 fs/fs_context.c:662
       vfs_get_tree+0x8c/0x370 fs/super.c:1771
       do_new_mount fs/namespace.c:3337 [inline]
       path_mount+0x1492/0x1ed0 fs/namespace.c:3664
       do_mount fs/namespace.c:3677 [inline]
       __do_sys_mount fs/namespace.c:3886 [inline]
       __se_sys_mount fs/namespace.c:3863 [inline]
       __x64_sys_mount+0x293/0x310 fs/namespace.c:3863
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0x40/0x110 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 kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2433/0x3b20 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
       inode_lock include/linux/fs.h:802 [inline]
       open_last_lookups fs/namei.c:3543 [inline]
       path_openat+0x8bd/0x2c50 fs/namei.c:3776
       do_filp_open+0x1de/0x430 fs/namei.c:3809
       do_sys_openat2+0x176/0x1e0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_openat fs/open.c:1468 [inline]
       __se_sys_openat fs/open.c:1463 [inline]
       __x64_sys_openat+0x175/0x210 fs/open.c:1463
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0x40/0x110 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#10

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_writers#10);
                               lock(&sbi->lock);
                               lock(sb_writers#10);
  lock(&type->i_mutex_dir_key#6);

 *** DEADLOCK ***

1 lock held by syz-executor233/5063:
 #0: ffff888079afc418 (sb_writers#10){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3535 [inline]
 #0: ffff888079afc418 (sb_writers#10){.+.+}-{0:0}, at: path_openat+0x19f6/0x2c50 fs/namei.c:3776

stack backtrace:
CPU: 0 PID: 5063 Comm: syz-executor233 Not tainted 6.7.0-rc5-syzkaller-00270-g0e389834672c #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+0xd9/0x1b0 lib/dump_stack.c:106
 check_noncircular+0x317/0x400 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:3869 [inline]
 __lock_acquire+0x2433/0x3b20 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
 down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
 inode_lock include/linux/fs.h:802 [inline]
 open_last_lookups fs/namei.c:3543 [inline]
 path_openat+0x8bd/0x2c50 fs/namei.c:3776
 do_filp_open+0x1de/0x430 fs/namei.c:3809
 do_sys_openat2+0x176/0x1e0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fd18844eb99
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 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:00007ffd0036c6d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd18844eb99
RDX: 000000000000275a RSI: 0000000020000280 RDI: 00000000ffffff9c
RBP: 00007fd1884c25f0 R08: 00000000200000c0 R09: 00005555566204c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd0036c700
R13: 00007ffd0036c928 R14: 431bde82d7b634db R15: 00007fd18849703b
 </TASK>