======================================================
WARNING: possible circular locking dependency detected
5.15.110-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/6234 is trying to acquire lock:
ffff0000d3b6c0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __do_sys_quotactl_fd fs/quota/quota.c:998 [inline]
ffff0000d3b6c0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __se_sys_quotactl_fd fs/quota/quota.c:971 [inline]
ffff0000d3b6c0e0 (&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:
ffff0000d3b6c460 (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.5/6234:
#0: ffff0000d3b6c460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377
stack backtrace:
CPU: 1 PID: 6234 Comm: syz-executor.5 Not tainted 5.15.110-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