syzbot

REISERFS (device loop3): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.1.52-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/12920 is trying to acquire lock:
ffff888022c58090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x76/0xd0 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff888070920980 (&type->i_mutex_dir_key#17/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
ffff888070920980 (&type->i_mutex_dir_key#17/1){+.+.}-{3:3}, at: filename_create+0x256/0x530 fs/namei.c:3807

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&type->i_mutex_dir_key#17/1){+.+.}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5661
       down_write_nested+0x39/0x60 kernel/locking/rwsem.c:1689
       inode_lock_nested include/linux/fs.h:791 [inline]
       filename_create+0x256/0x530 fs/namei.c:3807
       do_symlinkat+0xf6/0x600 fs/namei.c:4420
       __do_sys_symlinkat fs/namei.c:4447 [inline]
       __se_sys_symlinkat fs/namei.c:4444 [inline]
       __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4444
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (sb_writers#29){.+.+}-{0:0}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5661
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1832 [inline]
       sb_start_write+0x4d/0x1c0 include/linux/fs.h:1907
       mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437
       reiserfs_ioctl+0x170/0x340 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/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:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3824
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5048
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5661
       __mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
       reiserfs_write_lock+0x76/0xd0 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x15c/0x4b0 fs/reiserfs/namei.c:364
       __lookup_hash+0x117/0x240 fs/namei.c:1601
       filename_create+0x28d/0x530 fs/namei.c:3808
       do_symlinkat+0xf6/0x600 fs/namei.c:4420
       __do_sys_symlinkat fs/namei.c:4447 [inline]
       __se_sys_symlinkat fs/namei.c:4444 [inline]
       __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4444
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/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#29 --> &type->i_mutex_dir_key#17/1

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&type->i_mutex_dir_key#17/1);
                               lock(sb_writers#29);
                               lock(&type->i_mutex_dir_key#17/1);
  lock(&sbi->lock);

 *** DEADLOCK ***

2 locks held by syz-executor.3/12920:
 #0: ffff8880271c6460 (sb_writers#29){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
 #1: ffff888070920980 (&type->i_mutex_dir_key#17/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
 #1: ffff888070920980 (&type->i_mutex_dir_key#17/1){+.+.}-{3:3}, at: filename_create+0x256/0x530 fs/namei.c:3807

stack backtrace:
CPU: 0 PID: 12920 Comm: syz-executor.3 Not tainted 6.1.52-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3824
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5048
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5661
 __mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
 reiserfs_write_lock+0x76/0xd0 fs/reiserfs/lock.c:27
 reiserfs_lookup+0x15c/0x4b0 fs/reiserfs/namei.c:364
 __lookup_hash+0x117/0x240 fs/namei.c:1601
 filename_create+0x28d/0x530 fs/namei.c:3808
 do_symlinkat+0xf6/0x600 fs/namei.c:4420
 __do_sys_symlinkat fs/namei.c:4447 [inline]
 __se_sys_symlinkat fs/namei.c:4444 [inline]
 __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4444
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f14fa67cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f14fb4510c8 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f14fa79bf80 RCX: 00007f14fa67cae9
RDX: 00000000200000c0 RSI: ffffffffffffff9c RDI: 0000000020000080
RBP: 00007f14fa6c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f14fa79bf80 R15: 00007fff1e79f638
 </TASK>