syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.39-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/11206 is trying to acquire lock:
ffff000102213140 (&type->i_mutex_dir_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
ffff000102213140 (&type->i_mutex_dir_key#21){+.+.}-{3:3}, at: chown_common+0x358/0x7d8 fs/open.c:726

but task is already holding lock:
ffff000102c3c460 (sb_writers#25){.+.+}-{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#25){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1832 [inline]
       sb_start_write+0x7c/0x308 include/linux/fs.h:1907
       mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437
       reiserfs_ioctl+0x184/0x454 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+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 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:581

-> #1 (&sbi->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x21a0 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+0x130/0x3c4 fs/reiserfs/namei.c:364
       __lookup_slow+0x250/0x374 fs/namei.c:1685
       lookup_one_len+0x178/0x28c fs/namei.c:2711
       reiserfs_lookup_privroot+0x8c/0x204 fs/reiserfs/xattr.c:973
       reiserfs_fill_super+0x1bc0/0x2028 fs/reiserfs/super.c:2174
       mount_bdev+0x274/0x370 fs/super.c:1423
       get_super_block+0x44/0x58 fs/reiserfs/super.c:2601
       legacy_get_tree+0xd4/0x16c fs/fs_context.c:611
       vfs_get_tree+0x90/0x274 fs/super.c:1553
       do_new_mount+0x25c/0x8c4 fs/namespace.c:3040
       path_mount+0x590/0xe58 fs/namespace.c:3370
       do_mount fs/namespace.c:3383 [inline]
       __do_sys_mount fs/namespace.c:3591 [inline]
       __se_sys_mount fs/namespace.c:3568 [inline]
       __arm64_sys_mount+0x45c/0x594 fs/namespace.c:3568
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 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:581

-> #0 (&type->i_mutex_dir_key#21){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3098 [inline]
       check_prevs_add kernel/locking/lockdep.c:3217 [inline]
       validate_chain kernel/locking/lockdep.c:3832 [inline]
       __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
       lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669
       down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:756 [inline]
       chown_common+0x358/0x7d8 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+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 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:581

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#21 --> &sbi->lock --> sb_writers#25

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#25);
                               lock(&sbi->lock);
                               lock(sb_writers#25);
  lock(&type->i_mutex_dir_key#21);

 *** DEADLOCK ***

1 lock held by syz-executor.4/11206:
 #0: ffff000102c3c460 (sb_writers#25){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437

stack backtrace:
CPU: 0 PID: 11206 Comm: syz-executor.4 Not tainted 6.1.39-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2056
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3098 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain kernel/locking/lockdep.c:3832 [inline]
 __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669
 down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:756 [inline]
 chown_common+0x358/0x7d8 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+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 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:581