======================================================
WARNING: possible circular locking dependency detected
6.1.27-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/19960 is trying to acquire lock:
ffff88814c61c0e0 (&type->s_umount_key#32){++++}-{3:3}, at: __do_sys_quotactl_fd fs/quota/quota.c:999 [inline]
ffff88814c61c0e0 (&type->s_umount_key#32){++++}-{3:3}, at: __se_sys_quotactl_fd+0x24a/0x3b0 fs/quota/quota.c:972

but task is already holding lock:
ffff88814c61c460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#4){.+.+}-{0:0}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1832 [inline]
       sb_start_write include/linux/fs.h:1907 [inline]
       write_mmp_block+0xe1/0x930 fs/ext4/mmp.c:50
       ext4_multi_mount_protect+0x54a/0x990 fs/ext4/mmp.c:349
       __ext4_remount fs/ext4/super.c:6530 [inline]
       ext4_reconfigure+0x2d30/0x3610 fs/ext4/super.c:6629
       reconfigure_super+0x3c5/0x7c0 fs/super.c:957
       vfs_fsconfig_locked fs/fsopen.c:254 [inline]
       __do_sys_fsconfig fs/fsopen.c:439 [inline]
       __se_sys_fsconfig+0x98b/0xec0 fs/fsopen.c:314
       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 (&type->s_umount_key#32){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3098 [inline]
       check_prevs_add kernel/locking/lockdep.c:3217 [inline]
       validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
       down_read+0x39/0x50 kernel/locking/rwsem.c:1520
       __do_sys_quotactl_fd fs/quota/quota.c:999 [inline]
       __se_sys_quotactl_fd+0x24a/0x3b0 fs/quota/quota.c:972
       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:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#4);
                               lock(&type->s_umount_key#32);
                               lock(sb_writers#4);
  lock(&type->s_umount_key#32);

 *** DEADLOCK ***

1 lock held by syz-executor.2/19960:
 #0: ffff88814c61c460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393

stack backtrace:
CPU: 0 PID: 19960 Comm: syz-executor.2 Not tainted 6.1.27-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
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:2178
 check_prev_add kernel/locking/lockdep.c:3098 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
 down_read+0x39/0x50 kernel/locking/rwsem.c:1520
 __do_sys_quotactl_fd fs/quota/quota.c:999 [inline]
 __se_sys_quotactl_fd+0x24a/0x3b0 fs/quota/quota.c:972
 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: 0033:0x7f2bf288c169
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007f2bf13fe168 EFLAGS: 00000246 ORIG_RAX: 00000000000001bb
RAX: ffffffffffffffda RBX: 00007f2bf29abf80 RCX: 00007f2bf288c169
RDX: 0000000000000000 RSI: ffffffff80000901 RDI: 0000000000000003
RBP: 00007f2bf28e7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc427121ff R14: 00007f2bf13fe300 R15: 0000000000022000
 </TASK>