syzbot

REISERFS (device loop0): journal params: device loop0, size 512, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.173-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor101/4162 is trying to acquire lock:
ffff88806fdc02e0 (&type->i_mutex_dir_key#6){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:799 [inline]
ffff88806fdc02e0 (&type->i_mutex_dir_key#6){++++}-{3:3}, at: open_last_lookups fs/namei.c:3531 [inline]
ffff88806fdc02e0 (&type->i_mutex_dir_key#6){++++}-{3:3}, at: path_openat+0x815/0x2f20 fs/namei.c:3739

but task is already holding lock:
ffff8880783c0460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#9){.+.+}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1813 [inline]
       sb_start_write+0x4f/0x1c0 include/linux/fs.h:1883
       mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:421
       reiserfs_ioctl+0x170/0x340 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (&sbi->lock){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       reiserfs_write_lock+0x76/0xd0 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x15c/0x4b0 fs/reiserfs/namei.c:364
       __lookup_slow+0x275/0x3d0 fs/namei.c:1663
       lookup_one_len+0x187/0x2d0 fs/namei.c:2718
       reiserfs_lookup_privroot+0x85/0x1e0 fs/reiserfs/xattr.c:980
       reiserfs_fill_super+0x2224/0x2690 fs/reiserfs/super.c:2178
       mount_bdev+0x2c9/0x3f0 fs/super.c:1400
       legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
       do_mount fs/namespace.c:3355 [inline]
       __do_sys_mount fs/namespace.c:3563 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&type->i_mutex_dir_key#6){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       inode_lock_shared include/linux/fs.h:799 [inline]
       open_last_lookups fs/namei.c:3531 [inline]
       path_openat+0x815/0x2f20 fs/namei.c:3739
       do_filp_open+0x21c/0x460 fs/namei.c:3769
       do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
       do_sys_open fs/open.c:1269 [inline]
       __do_sys_open fs/open.c:1277 [inline]
       __se_sys_open fs/open.c:1273 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1273
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

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

 *** DEADLOCK ***

1 lock held by syz-executor101/4162:
 #0: ffff8880783c0460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377

stack backtrace:
CPU: 0 PID: 4162 Comm: syz-executor101 Not tainted 5.15.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
 inode_lock_shared include/linux/fs.h:799 [inline]
 open_last_lookups fs/namei.c:3531 [inline]
 path_openat+0x815/0x2f20 fs/namei.c:3739
 do_filp_open+0x21c/0x460 fs/namei.c:3769
 do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_open fs/open.c:1277 [inline]
 __se_sys_open fs/open.c:1273 [inline]
 __x64_sys_open+0x221/0x270 fs/open.c:1273
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7314f1c679
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:00007ffec46ae9b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffec46aeb88 RCX: 00007f7314f1c679
RDX: 0000000000000136 RSI: 0000000000004001 RDI: 0000000020000080
RBP: 00007f7314f90610 R08: 00007ffec46aeb88 R09: 00007ffec46aeb88
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffec46aeb78 R14: 0000000000000001 R15: 0