======================================================
WARNING: possible circular locking dependency detected
5.15.112-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/4952 is trying to acquire lock:
ffff88802494c0e0 (&type->s_umount_key#32){++++}-{3:3}, at: __do_sys_quotactl_fd fs/quota/quota.c:998 [inline]
ffff88802494c0e0 (&type->s_umount_key#32){++++}-{3:3}, at: __se_sys_quotactl_fd+0x24a/0x3b0 fs/quota/quota.c:971
but task is already holding lock:
ffff88802494c460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (sb_writers#5){.+.+}-{0:0}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
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+0xe3/0x940 fs/ext4/mmp.c:50
ext4_multi_mount_protect+0x54a/0x980 fs/ext4/mmp.c:351
ext4_remount+0x2723/0x2fb0 fs/ext4/super.c:5949
reconfigure_super+0x3c5/0x7c0 fs/super.c:916
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+0x61/0xcb
-> #0 (&type->s_umount_key#32){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
down_read+0x45/0x2e0 kernel/locking/rwsem.c:1488
__do_sys_quotactl_fd fs/quota/quota.c:998 [inline]
__se_sys_quotactl_fd+0x24a/0x3b0 fs/quota/quota.c:971
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+0x61/0xcb
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sb_writers#5);
lock(&type->s_umount_key#32);
lock(sb_writers#5);
lock(&type->s_umount_key#32);
*** DEADLOCK ***
1 lock held by syz-executor.1/4952:
#0: ffff88802494c460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
stack backtrace:
CPU: 0 PID: 4952 Comm: syz-executor.1 Not tainted 5.15.112-syzkaller #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+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2f8/0x3b0 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+0x1646/0x58b0 kernel/locking/lockdep.c:3787
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
down_read+0x45/0x2e0 kernel/locking/rwsem.c:1488
__do_sys_quotactl_fd fs/quota/quota.c:998 [inline]
__se_sys_quotactl_fd+0x24a/0x3b0 fs/quota/quota.c:971
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+0x61/0xcb
RIP: 0033:0x7f61b5815169
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:00007f61b3d45168 EFLAGS: 00000246 ORIG_RAX: 00000000000001bb
RAX: ffffffffffffffda RBX: 00007f61b5935120 RCX: 00007f61b5815169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007f61b5870ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffde794e73f R14: 00007f61b3d45300 R15: 0000000000022000
</TASK>