======================================================
WARNING: possible circular locking dependency detected
6.4.0-rc1-syzkaller-00138-gd4d58949a6ea #0 Not tainted
------------------------------------------------------
syz-executor.4/9327 is trying to acquire lock:
ffff88802d0460e0 (&type->s_umount_key#50){++++}-{3:3}, at: __do_sys_quotactl_fd+0x174/0x3f0 fs/quota/quota.c:997

but task is already holding lock:
ffff88802d046460 (sb_writers#5){.+.+}-{0:0}, at: __do_sys_quotactl_fd+0xd3/0x3f0 fs/quota/quota.c:990

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#5){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1494 [inline]
       sb_start_write include/linux/fs.h:1569 [inline]
       write_mmp_block+0xc4/0x820 fs/ext4/mmp.c:50
       ext4_multi_mount_protect+0x50d/0xac0 fs/ext4/mmp.c:347
       __ext4_remount fs/ext4/super.c:6578 [inline]
       ext4_reconfigure+0x242b/0x2b60 fs/ext4/super.c:6677
       reconfigure_super+0x40c/0xa30 fs/super.c:956
       vfs_fsconfig_locked fs/fsopen.c:254 [inline]
       __do_sys_fsconfig+0xa5e/0xc50 fs/fsopen.c:439
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&type->s_umount_key#50){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3108 [inline]
       check_prevs_add kernel/locking/lockdep.c:3227 [inline]
       validate_chain kernel/locking/lockdep.c:3842 [inline]
       __lock_acquire+0x2f21/0x5df0 kernel/locking/lockdep.c:5074
       lock_acquire kernel/locking/lockdep.c:5691 [inline]
       lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5656
       down_write+0x92/0x200 kernel/locking/rwsem.c:1573
       __do_sys_quotactl_fd+0x174/0x3f0 fs/quota/quota.c:997
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 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
       ----                    ----
  rlock(sb_writers#5);
                               lock(&type->s_umount_key#50);
                               lock(sb_writers#5);
  lock(&type->s_umount_key#50);

 *** DEADLOCK ***

1 lock held by syz-executor.4/9327:
 #0: ffff88802d046460 (sb_writers#5){.+.+}-{0:0}, at: __do_sys_quotactl_fd+0xd3/0x3f0 fs/quota/quota.c:990

stack backtrace:
CPU: 1 PID: 9327 Comm: syz-executor.4 Not tainted 6.4.0-rc1-syzkaller-00138-gd4d58949a6ea #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2188
 check_prev_add kernel/locking/lockdep.c:3108 [inline]
 check_prevs_add kernel/locking/lockdep.c:3227 [inline]
 validate_chain kernel/locking/lockdep.c:3842 [inline]
 __lock_acquire+0x2f21/0x5df0 kernel/locking/lockdep.c:5074
 lock_acquire kernel/locking/lockdep.c:5691 [inline]
 lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5656
 down_write+0x92/0x200 kernel/locking/rwsem.c:1573
 __do_sys_quotactl_fd+0x174/0x3f0 fs/quota/quota.c:997
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f552ae8c169
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:00007f552bc1e168 EFLAGS: 00000246 ORIG_RAX: 00000000000001bb
RAX: ffffffffffffffda RBX: 00007f552afabf80 RCX: 00007f552ae8c169
RDX: 000000000000ee01 RSI: ffffffff80000302 RDI: 0000000000000004
RBP: 00007f552aee7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd44dd596f R14: 00007f552bc1e300 R15: 0000000000022000
 </TASK>