BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! turning off the locking correctness validator. CPU: 0 PID: 13212 Comm: syz-executor.0 Not tainted 5.6.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 add_chain_cache kernel/locking/lockdep.c:2840 [inline] lookup_chain_cache_add kernel/locking/lockdep.c:2914 [inline] validate_chain kernel/locking/lockdep.c:2935 [inline] __lock_acquire.cold+0x263/0x288 kernel/locking/lockdep.c:3954 lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4484 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] netif_addr_lock_bh include/linux/netdevice.h:4163 [inline] __dev_mc_del+0x28/0xd0 net/core/dev_addr_lists.c:805 igmp6_group_dropped+0x2f5/0x9b0 net/ipv6/mcast.c:708 ipv6_mc_down+0x5c/0x120 net/ipv6/mcast.c:2541 ipv6_mc_destroy_dev+0x1a/0x160 net/ipv6/mcast.c:2603 addrconf_ifdown+0xd8a/0x12f0 net/ipv6/addrconf.c:3846 addrconf_notify+0x5cd/0x2310 net/ipv6/addrconf.c:3637 notifier_call_chain+0xc0/0x230 kernel/notifier.c:83 call_netdevice_notifiers_info net/core/dev.c:1948 [inline] call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1933 call_netdevice_notifiers_extack net/core/dev.c:1960 [inline] call_netdevice_notifiers net/core/dev.c:1974 [inline] rollback_registered_many+0x75c/0xe70 net/core/dev.c:8826 rollback_registered+0xf2/0x1c0 net/core/dev.c:8871 unregister_netdevice_queue net/core/dev.c:9963 [inline] unregister_netdevice_queue+0x1d7/0x2b0 net/core/dev.c:9956 unregister_netdevice include/linux/netdevice.h:2716 [inline] __tun_detach+0xe42/0x1110 drivers/net/tun.c:690 tun_detach drivers/net/tun.c:707 [inline] tun_chr_close+0xd9/0x180 drivers/net/tun.c:3410 __fput+0x2da/0x850 fs/file_table.c:280 task_work_run+0x13f/0x1b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x2fa/0x360 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f630be8dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00007f630be8e6d4 RCX: 000000000045c849 RDX: 0000000020000000 RSI: 00000000400454ca RDI: 0000000000000005 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000005a1 R14: 00000000004c83a9 R15: 000000000076bf0c