======================================================
WARNING: possible circular locking dependency detected
5.15.111-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/16970 is trying to acquire lock:
ffff0000d45ac0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __do_sys_quotactl_fd fs/quota/quota.c:998 [inline]
ffff0000d45ac0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __se_sys_quotactl_fd fs/quota/quota.c:971 [inline]
ffff0000d45ac0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __arm64_sys_quotactl_fd+0x30c/0x4a4 fs/quota/quota.c:971

but task is already holding lock:
ffff0000d45ac460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#3){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1742 [inline]
       sb_start_write include/linux/fs.h:1812 [inline]
       write_mmp_block+0x170/0xd18 fs/ext4/mmp.c:50
       ext4_multi_mount_protect+0x2e0/0x894 fs/ext4/mmp.c:351
       ext4_remount+0x1fc8/0x2710 fs/ext4/super.c:5951
       legacy_reconfigure+0xfc/0x114 fs/fs_context.c:633
       reconfigure_super+0x340/0x690 fs/super.c:916
       vfs_fsconfig_locked fs/fsopen.c:254 [inline]
       __do_sys_fsconfig fs/fsopen.c:439 [inline]
       __se_sys_fsconfig fs/fsopen.c:314 [inline]
       __arm64_sys_fsconfig+0xa1c/0xd18 fs/fsopen.c:314
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&type->s_umount_key#30){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3787 [inline]
       __lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
       down_read+0xbc/0x11c kernel/locking/rwsem.c:1488
       __do_sys_quotactl_fd fs/quota/quota.c:998 [inline]
       __se_sys_quotactl_fd fs/quota/quota.c:971 [inline]
       __arm64_sys_quotactl_fd+0x30c/0x4a4 fs/quota/quota.c:971
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#3);
                               lock(&type->s_umount_key#30);
                               lock(sb_writers#3);
  lock(&type->s_umount_key#30);

 *** DEADLOCK ***

1 lock held by syz-executor.1/16970:
 #0: ffff0000d45ac460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377

stack backtrace:
CPU: 1 PID: 16970 Comm: syz-executor.1 Not tainted 5.15.111-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __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:2011
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3787 [inline]
 __lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
 down_read+0xbc/0x11c kernel/locking/rwsem.c:1488
 __do_sys_quotactl_fd fs/quota/quota.c:998 [inline]
 __se_sys_quotactl_fd fs/quota/quota.c:971 [inline]
 __arm64_sys_quotactl_fd+0x30c/0x4a4 fs/quota/quota.c:971
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584