syzbot

REISERFS warning (device loop7): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 1) not found (pos 2)
REISERFS (device loop7): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.1.141-syzkaller #0 Not tainted
------------------------------------------------------
syz.7.914/8446 is trying to acquire lock:
ffff0000e36082e0 (&type->i_mutex_dir_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff0000e36082e0 (&type->i_mutex_dir_key#21){+.+.}-{3:3}, at: chown_common+0x2ac/0x574 fs/open.c:726

but task is already holding lock:
ffff0000c4142460 (sb_writers#33){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#33){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1891 [inline]
       sb_start_write+0x74/0x2ac include/linux/fs.h:1966
       mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437
       reiserfs_ioctl+0x114/0x450 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]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #1 (&sbi->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x1f38 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x11c/0x378 fs/reiserfs/namei.c:364
       __lookup_slow+0x24c/0x370 fs/namei.c:1690
       lookup_one_len+0x178/0x28c fs/namei.c:2740
       reiserfs_lookup_privroot+0x8c/0x204 fs/reiserfs/xattr.c:973
       reiserfs_fill_super+0x18ec/0x1d40 fs/reiserfs/super.c:2174
       mount_bdev+0x264/0x358 fs/super.c:1443
       get_super_block+0x44/0x58 fs/reiserfs/super.c:2601
       legacy_get_tree+0xd4/0x16c fs/fs_context.c:632
       vfs_get_tree+0x90/0x274 fs/super.c:1573
       do_new_mount+0x228/0x810 fs/namespace.c:3054
       path_mount+0x5b4/0xe78 fs/namespace.c:3384
       do_mount fs/namespace.c:3397 [inline]
       __do_sys_mount fs/namespace.c:3605 [inline]
       __se_sys_mount fs/namespace.c:3582 [inline]
       __arm64_sys_mount+0x49c/0x584 fs/namespace.c:3582
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (&type->i_mutex_dir_key#21){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x293c/0x6544 kernel/locking/lockdep.c:5049
       lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662
       down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       chown_common+0x2ac/0x574 fs/open.c:726
       vfs_fchown fs/open.c:804 [inline]
       ksys_fchown+0xe0/0x158 fs/open.c:815
       __do_sys_fchown fs/open.c:823 [inline]
       __se_sys_fchown fs/open.c:821 [inline]
       __arm64_sys_fchown+0x7c/0x94 fs/open.c:821
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#21 --> &sbi->lock --> sb_writers#33

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#33);
                               lock(&sbi->lock);
                               lock(sb_writers#33);
  lock(&type->i_mutex_dir_key#21);

 *** DEADLOCK ***

1 lock held by syz.7.914/8446:
 #0: ffff0000c4142460 (sb_writers#33){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437

stack backtrace:
CPU: 0 PID: 8446 Comm: syz.7.914 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048
 check_noncircular+0x240/0x2d4 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 kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x293c/0x6544 kernel/locking/lockdep.c:5049
 lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662
 down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:758 [inline]
 chown_common+0x2ac/0x574 fs/open.c:726
 vfs_fchown fs/open.c:804 [inline]
 ksys_fchown+0xe0/0x158 fs/open.c:815
 __do_sys_fchown fs/open.c:823 [inline]
 __se_sys_fchown fs/open.c:821 [inline]
 __arm64_sys_fchown+0x7c/0x94 fs/open.c:821
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
REISERFS warning (device loop7): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 1) not found (pos 2)
REISERFS warning (device loop7): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 1) not found (pos 2)