====================================================== WARNING: possible circular locking dependency detected 6.1.27-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/12035 is trying to acquire lock: ffff00010034e460 (sb_writers#3){.+.+}-{0:0}, at: ext4_multi_mount_protect+0x2e0/0x8a4 fs/ext4/mmp.c:349 but task is already holding lock: ffff00010034e0e0 (&type->s_umount_key#30){++++}-{3:3}, at: vfs_fsconfig_locked fs/fsopen.c:253 [inline] ffff00010034e0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:439 [inline] ffff00010034e0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline] ffff00010034e0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __arm64_sys_fsconfig+0xa14/0xd18 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#30){++++}-{3:3}: down_read+0x5c/0x78 kernel/locking/rwsem.c:1520 __do_sys_quotactl_fd fs/quota/quota.c:999 [inline] __se_sys_quotactl_fd fs/quota/quota.c:972 [inline] __arm64_sys_quotactl_fd+0x30c/0x4a4 fs/quota/quota.c:972 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 -> #0 (sb_writers#3){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1832 [inline] sb_start_write include/linux/fs.h:1907 [inline] write_mmp_block+0x100/0xb8c fs/ext4/mmp.c:50 ext4_multi_mount_protect+0x2e0/0x8a4 fs/ext4/mmp.c:349 __ext4_remount fs/ext4/super.c:6530 [inline] ext4_reconfigure+0x218c/0x2934 fs/ext4/super.c:6629 reconfigure_super+0x328/0x738 fs/super.c:957 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+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&type->s_umount_key#30); lock(sb_writers#3); lock(&type->s_umount_key#30); lock(sb_writers#3); *** DEADLOCK *** 2 locks held by syz-executor.2/12035: #0: ffff0000dd17a070 (&fc->uapi_mutex){+.+.}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:437 [inline] #0: ffff0000dd17a070 (&fc->uapi_mutex){+.+.}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline] #0: ffff0000dd17a070 (&fc->uapi_mutex){+.+.}-{3:3}, at: __arm64_sys_fsconfig+0x720/0xd18 fs/fsopen.c:314 #1: ffff00010034e0e0 (&type->s_umount_key#30){++++}-{3:3}, at: vfs_fsconfig_locked fs/fsopen.c:253 [inline] #1: ffff00010034e0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:439 [inline] #1: ffff00010034e0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline] #1: ffff00010034e0e0 (&type->s_umount_key#30){++++}-{3:3}, at: __arm64_sys_fsconfig+0xa14/0xd18 fs/fsopen.c:314 stack backtrace: CPU: 0 PID: 12035 Comm: syz-executor.2 Not tainted 6.1.27-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2056 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1832 [inline] sb_start_write include/linux/fs.h:1907 [inline] write_mmp_block+0x100/0xb8c fs/ext4/mmp.c:50 ext4_multi_mount_protect+0x2e0/0x8a4 fs/ext4/mmp.c:349 __ext4_remount fs/ext4/super.c:6530 [inline] ext4_reconfigure+0x218c/0x2934 fs/ext4/super.c:6629 reconfigure_super+0x328/0x738 fs/super.c:957 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+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 EXT4-fs (loop2): re-mounted. Quota mode: writeback.