EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc1-syzkaller #0 Tainted: G        W         
------------------------------------------------------
syz-executor.1/4793 is trying to acquire lock:
ff60000027acc460 (sb_writers#4){.+.+}-{0:0}, at: ext4_multi_mount_protect+0x3e8/0x74a fs/ext4/mmp.c:343

but task is already holding lock:
ff60000027acc0e0 (&type->s_umount_key#31){++++}-{3:3}, at: vfs_fsconfig_locked fs/fsopen.c:253 [inline]
ff60000027acc0e0 (&type->s_umount_key#31){++++}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:439 [inline]
ff60000027acc0e0 (&type->s_umount_key#31){++++}-{3:3}, at: sys_fsconfig+0x878/0x93a fs/fsopen.c:314

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&type->s_umount_key#31){++++}-{3:3}:
       lock_acquire.part.0+0x1d0/0x424 kernel/locking/lockdep.c:5668
       lock_acquire+0x54/0x6a kernel/locking/lockdep.c:5641
       down_read+0x3c/0x54 kernel/locking/rwsem.c:1509
       __do_sys_quotactl_fd fs/quota/quota.c:999 [inline]
       sys_quotactl_fd+0x282/0x360 fs/quota/quota.c:972
       ret_from_syscall+0x0/0x2

-> #0 (sb_writers#4){.+.+}-{0:0}:
       check_noncircular+0x1de/0x1fe kernel/locking/lockdep.c:2177
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain kernel/locking/lockdep.c:3831 [inline]
       __lock_acquire+0x198a/0x347a kernel/locking/lockdep.c:5055
       lock_acquire.part.0+0x1d0/0x424 kernel/locking/lockdep.c:5668
       lock_acquire+0x54/0x6a kernel/locking/lockdep.c:5641
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1811 [inline]
       sb_start_write include/linux/fs.h:1886 [inline]
       write_mmp_block+0xc8/0x7c4 fs/ext4/mmp.c:50
       ext4_multi_mount_protect+0x3e8/0x74a fs/ext4/mmp.c:343
       __ext4_remount fs/ext4/super.c:6513 [inline]
       ext4_reconfigure+0x15b8/0x165a fs/ext4/super.c:6612
       reconfigure_super+0x1c8/0x492 fs/super.c:935
       vfs_fsconfig_locked fs/fsopen.c:254 [inline]
       __do_sys_fsconfig fs/fsopen.c:439 [inline]
       sys_fsconfig+0x87e/0x93a fs/fsopen.c:314
       ret_from_syscall+0x0/0x2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&type->s_umount_key#31);
                               lock(sb_writers#4);
                               lock(&type->s_umount_key#31);
  lock(sb_writers#4);

 *** DEADLOCK ***

2 locks held by syz-executor.1/4793:
 #0: ff60000012312870 (&fc->uapi_mutex){+.+.}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:437 [inline]
 #0: ff60000012312870 (&fc->uapi_mutex){+.+.}-{3:3}, at: sys_fsconfig+0x46c/0x93a fs/fsopen.c:314
 #1: ff60000027acc0e0 (&type->s_umount_key#31){++++}-{3:3}, at: vfs_fsconfig_locked fs/fsopen.c:253 [inline]
 #1: ff60000027acc0e0 (&type->s_umount_key#31){++++}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:439 [inline]
 #1: ff60000027acc0e0 (&type->s_umount_key#31){++++}-{3:3}, at: sys_fsconfig+0x878/0x93a fs/fsopen.c:314

stack backtrace:
CPU: 1 PID: 4793 Comm: syz-executor.1 Tainted: G        W          6.2.0-rc1-syzkaller #0
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
[<ffffffff8000b9ea>] dump_backtrace+0x2e/0x3c arch/riscv/kernel/stacktrace.c:121
[<ffffffff83402b96>] show_stack+0x34/0x40 arch/riscv/kernel/stacktrace.c:127
[<ffffffff83442726>] __dump_stack lib/dump_stack.c:88 [inline]
[<ffffffff83442726>] dump_stack_lvl+0xe0/0x14c lib/dump_stack.c:106
[<ffffffff834427ae>] dump_stack+0x1c/0x24 lib/dump_stack.c:113
[<ffffffff8012199a>] print_circular_bug+0x370/0x3fa kernel/locking/lockdep.c:2055
[<ffffffff80121c02>] check_noncircular+0x1de/0x1fe kernel/locking/lockdep.c:2177
[<ffffffff80125e68>] check_prev_add kernel/locking/lockdep.c:3097 [inline]
[<ffffffff80125e68>] check_prevs_add kernel/locking/lockdep.c:3216 [inline]
[<ffffffff80125e68>] validate_chain kernel/locking/lockdep.c:3831 [inline]
[<ffffffff80125e68>] __lock_acquire+0x198a/0x347a kernel/locking/lockdep.c:5055
[<ffffffff80128932>] lock_acquire.part.0+0x1d0/0x424 kernel/locking/lockdep.c:5668
[<ffffffff80128bda>] lock_acquire+0x54/0x6a kernel/locking/lockdep.c:5641
[<ffffffff807bc944>] percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
[<ffffffff807bc944>] __sb_start_write include/linux/fs.h:1811 [inline]
[<ffffffff807bc944>] sb_start_write include/linux/fs.h:1886 [inline]
[<ffffffff807bc944>] write_mmp_block+0xc8/0x7c4 fs/ext4/mmp.c:50
[<ffffffff807bdc46>] ext4_multi_mount_protect+0x3e8/0x74a fs/ext4/mmp.c:343
[<ffffffff808173b8>] __ext4_remount fs/ext4/super.c:6513 [inline]
[<ffffffff808173b8>] ext4_reconfigure+0x15b8/0x165a fs/ext4/super.c:6612
[<ffffffff80551994>] reconfigure_super+0x1c8/0x492 fs/super.c:935
[<ffffffff805e2c90>] vfs_fsconfig_locked fs/fsopen.c:254 [inline]
[<ffffffff805e2c90>] __do_sys_fsconfig fs/fsopen.c:439 [inline]
[<ffffffff805e2c90>] sys_fsconfig+0x87e/0x93a fs/fsopen.c:314
[<ffffffff80005ff6>] ret_from_syscall+0x0/0x2
EXT4-fs warning (device loop1): ext4_enable_quotas:6967: Failed to enable quota tracking (type=2, err=-22, ino=15). Please run e2fsck to fix.