------------[ cut here ]------------ lockdep bfs error:-1 WARNING: CPU: 0 PID: 5406 at kernel/locking/lockdep.c:2071 print_bfs_bug+0x22/0x30 kernel/locking/lockdep.c:2071 Modules linked in: CPU: 0 PID: 5406 Comm: syz-executor.3 Not tainted 6.8.0-rc6-syzkaller-gd206a76d7d27 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 RIP: 0010:print_bfs_bug+0x22/0x30 kernel/locking/lockdep.c:2071 Code: 0f 1f 84 00 00 00 00 00 55 53 89 fb e8 97 8a df 02 89 c5 e8 80 b8 fe ff 85 ed 74 10 48 c7 c7 20 3d 2c 8b 89 de e8 be 7d e6 ff <0f> 0b 5b 5d c3 66 0f 1f 84 00 00 00 00 00 55 41 57 41 56 41 55 41 RSP: 0018:ffffc90004b5efe8 EFLAGS: 00010046 RAX: ad3de0aa8811a400 RBX: 00000000ffffffff RCX: ffff88801ec28000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffffff81548dae R09: 1ffff110173051a2 R10: dffffc0000000000 R11: ffffed10173051a3 R12: 000000000003b301 R13: ffffffff91b26b18 R14: ffffffff90652a20 R15: ffffffff91a3d188 FS: 0000555556bea480(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffce7f736ac CR3: 0000000076a0a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: check_prev_add kernel/locking/lockdep.c:3138 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x6aab/0x7fb0 kernel/locking/lockdep.c:5137 lock_acquire+0x1df/0x520 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 alloc_object+0x1ba/0x6c0 lib/debugobjects.c:233 lookup_object_or_alloc lib/debugobjects.c:587 [inline] debug_object_activate+0x140/0x4f0 lib/debugobjects.c:710 debug_rcu_head_queue kernel/rcu/rcu.h:227 [inline] __call_rcu_common kernel/rcu/tree.c:2700 [inline] call_rcu+0x93/0xa70 kernel/rcu/tree.c:2829 thread_stack_delayed_free kernel/fork.c:228 [inline] free_thread_stack kernel/fork.c:334 [inline] release_task_stack kernel/fork.c:569 [inline] put_task_stack+0x143/0x1f0 kernel/fork.c:576 finish_task_switch+0x36f/0x820 kernel/sched/core.c:5307 context_switch kernel/sched/core.c:5403 [inline] __schedule+0x1a47/0x4b50 kernel/sched/core.c:6727 preempt_schedule_irq+0xf7/0x1b0 kernel/sched/core.c:7047 irqentry_exit+0x53/0x80 kernel/entry/common.c:348 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:654 RIP: 0010:legitimize_links+0x29d/0x410 fs/namei.c:732 Code: e9 62 ff ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 78 ff ff ff 4c 89 ff e8 0f fc ea ff e9 6b ff ff ff e8 85 38 8b ff eb 05 7e 38 8b ff b0 01 48 83 c4 38 5b 41 5c 41 5d 41 5e 41 5f 5d c3 RSP: 0018:ffffc90004b5fac8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff9200096bf9e RDX: ffff88801ec28000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffff82032e56 R09: ffff888063ff1a08 R10: ffff88801fbccfe0 R11: ffff888063ff1a08 R12: 1ffff9200096bf95 R13: ffffc90004b5fca0 R14: ffffc90004b5fca0 R15: ffffc90004b5fcf4 try_to_unlazy+0x7a/0x5b0 fs/namei.c:780 complete_walk+0x118/0x360 fs/namei.c:891 path_lookupat+0x24b/0x450 fs/namei.c:2493 filename_lookup+0x251/0x600 fs/namei.c:2515 user_path_at_empty+0x3e/0x60 fs/namei.c:2924 user_path_at include/linux/namei.h:57 [inline] ksys_umount fs/namespace.c:1916 [inline] __do_sys_umount fs/namespace.c:1924 [inline] __se_sys_umount fs/namespace.c:1922 [inline] __x64_sys_umount+0xf0/0x170 fs/namespace.c:1922 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x81/0x180 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f3c6a47f0d7 Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffce7f73698 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 00007f3c6a4c93b9 RCX: 00007f3c6a47f0d7 RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffce7f74810 RBP: 00007ffce7f747ec R08: 0000000000000000 R09: 00007ffce7ff00b0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffce7f74810 R13: 00007f3c6a4c93b9 R14: 00000000000525c8 R15: 000000000000000b ---------------- Code disassembly (best guess): 0: e9 62 ff ff ff jmp 0xffffff67 5: 44 89 f9 mov %r15d,%ecx 8: 80 e1 07 and $0x7,%cl b: 80 c1 03 add $0x3,%cl e: 38 c1 cmp %al,%cl 10: 0f 8c 78 ff ff ff jl 0xffffff8e 16: 4c 89 ff mov %r15,%rdi 19: e8 0f fc ea ff call 0xffeafc2d 1e: e9 6b ff ff ff jmp 0xffffff8e 23: e8 85 38 8b ff call 0xff8b38ad 28: eb 05 jmp 0x2f * 2a: e8 7e 38 8b ff call 0xff8b38ad <-- trapping instruction 2f: b0 01 mov $0x1,%al 31: 48 83 c4 38 add $0x38,%rsp 35: 5b pop %rbx 36: 41 5c pop %r12 38: 41 5d pop %r13 3a: 41 5e pop %r14 3c: 41 5f pop %r15 3e: 5d pop %rbp 3f: c3 ret