EXT4-fs (loop7): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.7.831/8226 is trying to acquire lock: ffff0000f21b0160 (&ovl_i_mutex_key[depth]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline] ffff0000f21b0160 (&ovl_i_mutex_key[depth]){+.+.}-{4:4}, at: lock_two_nondirectories+0xc4/0x148 fs/inode.c:1254 but task is already holding lock: ffff0000f278a410 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0xdc fs/namespace.c:537 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (sb_writers#3){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write include/linux/fs/super.h:125 [inline] ovl_start_write+0xf0/0x324 fs/overlayfs/util.c:32 ovl_do_copy_up fs/overlayfs/copy_up.c:977 [inline] ovl_copy_up_one fs/overlayfs/copy_up.c:1189 [inline] ovl_copy_up_flags+0x980/0x28a4 fs/overlayfs/copy_up.c:1243 ovl_maybe_copy_up+0x108/0x148 fs/overlayfs/copy_up.c:1272 ovl_open+0x12c/0x2c0 fs/overlayfs/file.c:211 do_dentry_open+0x5c4/0xfc8 fs/open.c:947 vfs_open+0x44/0x2d4 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x2234/0x2a6c fs/namei.c:4858 do_file_open+0x1c4/0x2e4 fs/namei.c:4887 do_sys_openat2+0x114/0x1e8 fs/open.c:1364 do_sys_open+0xac/0xdc fs/open.c:1370 __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __arm64_sys_openat+0x9c/0xb8 fs/open.c:1381 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #1 (&ovl_i_lock_key[depth]){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_interruptible_nested+0x24/0x30 kernel/locking/mutex.c:898 ovl_inode_lock_interruptible fs/overlayfs/overlayfs.h:705 [inline] ovl_nlink_start+0xc8/0x350 fs/overlayfs/util.c:1173 ovl_do_remove+0x1c0/0xa04 fs/overlayfs/dir.c:954 ovl_unlink+0x24/0x34 fs/overlayfs/dir.c:988 vfs_unlink+0x208/0x580 fs/namei.c:5498 filename_unlinkat+0x2dc/0x458 fs/namei.c:5568 __do_sys_unlinkat fs/namei.c:5597 [inline] __se_sys_unlinkat fs/namei.c:5589 [inline] __arm64_sys_unlinkat+0xdc/0x104 fs/namei.c:5589 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #0 (&ovl_i_mutex_key[depth]){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 down_write+0x50/0xc0 kernel/locking/rwsem.c:1625 inode_lock include/linux/fs.h:1029 [inline] lock_two_nondirectories+0xc4/0x148 fs/inode.c:1254 ext4_move_extents+0x194/0x3580 fs/ext4/move_extent.c:589 __ext4_ioctl fs/ext4/ioctl.c:1657 [inline] ext4_ioctl+0x2a14/0x4234 fs/ext4/ioctl.c:1922 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 other info that might help us debug this: Chain exists of: &ovl_i_mutex_key[depth] --> &ovl_i_lock_key[depth] --> sb_writers#3 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#3); lock(&ovl_i_lock_key[depth]); lock(sb_writers#3); lock(&ovl_i_mutex_key[depth]); *** DEADLOCK *** 1 lock held by syz.7.831/8226: #0: ffff0000f278a410 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0xdc fs/namespace.c:537 stack backtrace: CPU: 1 UID: 0 PID: 8226 Comm: syz.7.831 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x328/0x330 kernel/locking/lockdep.c:2043 check_noncircular+0x158/0x174 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 down_write+0x50/0xc0 kernel/locking/rwsem.c:1625 inode_lock include/linux/fs.h:1029 [inline] lock_two_nondirectories+0xc4/0x148 fs/inode.c:1254 ext4_move_extents+0x194/0x3580 fs/ext4/move_extent.c:589 __ext4_ioctl fs/ext4/ioctl.c:1657 [inline] ext4_ioctl+0x2a14/0x4234 fs/ext4/ioctl.c:1922 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594