syzbot

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reiserfs: enabling write barrier flush mode
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
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WARNING: possible circular locking dependency detected
6.4.0-rc7-syzkaller-00194-g8a28a0b6f1a1 #0 Not tainted
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syz-executor353/4998 is trying to acquire lock:
ffff888077ef82e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:775 [inline]
ffff888077ef82e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: open_last_lookups fs/namei.c:3557 [inline]
ffff888077ef82e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: path_openat+0x90f/0x2750 fs/namei.c:3788

but task is already holding lock:
ffff888079680460 (sb_writers#9){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3549 [inline]
ffff888079680460 (sb_writers#9){.+.+}-{0:0}, at: path_openat+0x2716/0x2750 fs/namei.c:3788

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#9){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1494 [inline]
       sb_start_write include/linux/fs.h:1569 [inline]
       mnt_want_write_file+0x92/0x5d0 fs/namespace.c:438
       reiserfs_ioctl+0x1a2/0x330 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+0x197/0x210 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

-> #1 (&sbi->lock){+.+.}-{3:3}:
       __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_slow+0x24c/0x460 fs/namei.c:1690
       lookup_one_len+0x16e/0x1a0 fs/namei.c:2742
       reiserfs_lookup_privroot+0x96/0x210 fs/reiserfs/xattr.c:976
       reiserfs_fill_super+0x1a8d/0x2eb0 fs/reiserfs/super.c:2192
       mount_bdev+0x358/0x420 fs/super.c:1380
       legacy_get_tree+0x109/0x220 fs/fs_context.c:610
       vfs_get_tree+0x8d/0x350 fs/super.c:1510
       do_new_mount fs/namespace.c:3039 [inline]
       path_mount+0x134b/0x1e40 fs/namespace.c:3369
       do_mount fs/namespace.c:3382 [inline]
       __do_sys_mount fs/namespace.c:3591 [inline]
       __se_sys_mount fs/namespace.c:3568 [inline]
       __x64_sys_mount+0x283/0x300 fs/namespace.c:3568
       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 (&type->i_mutex_dir_key#6){+.+.}-{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
       down_write+0x92/0x200 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:775 [inline]
       open_last_lookups fs/namei.c:3557 [inline]
       path_openat+0x90f/0x2750 fs/namei.c:3788
       do_filp_open+0x1ba/0x410 fs/namei.c:3818
       do_sys_openat2+0x16d/0x4c0 fs/open.c:1356
       do_sys_open fs/open.c:1372 [inline]
       __do_sys_openat fs/open.c:1388 [inline]
       __se_sys_openat fs/open.c:1383 [inline]
       __x64_sys_openat+0x143/0x1f0 fs/open.c:1383
       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:
  &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-executor353/4998:
 #0: ffff888079680460 (sb_writers#9){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3549 [inline]
 #0: ffff888079680460 (sb_writers#9){.+.+}-{0:0}, at: path_openat+0x2716/0x2750 fs/namei.c:3788

stack backtrace:
CPU: 1 PID: 4998 Comm: syz-executor353 Not tainted 6.4.0-rc7-syzkaller-00194-g8a28a0b6f1a1 #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
 down_write+0x92/0x200 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:775 [inline]
 open_last_lookups fs/namei.c:3557 [inline]
 path_openat+0x90f/0x2750 fs/namei.c:3788
 do_filp_open+0x1ba/0x410 fs/namei.c:3818
 do_sys_openat2+0x16d/0x4c0 fs/open.c:1356
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x143/0x1f0 fs/open.c:1383
 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: 0033:0x7fb7e8e4f8f9
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:00007ffecde0f678 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb7e8e4f8f9
RDX: 000000000000275a RSI: 0000000020000280 RDI: 00000000ffffff9c
RBP: 00007fb7e8e0f190 R08: 00000000200000c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb7e8e0f220