BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! turning off the locking correctness validator. CPU: 1 PID: 23354 Comm: syz-executor933 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 include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] kfree_call_rcu+0x2a9/0x400 kernel/rcu/tree.c:2855 __hw_addr_del_entry net/core/dev_addr_lists.c:107 [inline] __hw_addr_del_entry+0x2dd/0x3b0 net/core/dev_addr_lists.c:88 __hw_addr_del_ex+0x129/0x150 net/core/dev_addr_lists.c:121 __dev_mc_del+0x74/0xd0 net/core/dev_addr_lists.c:806 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:3848 addrconf_notify+0x5cd/0x2310 net/ipv6/addrconf.c:3639 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:8810 rollback_registered+0xf2/0x1c0 net/core/dev.c:8855 unregister_netdevice_queue net/core/dev.c:9947 [inline] unregister_netdevice_queue+0x1d7/0x2b0 net/core/dev.c:9940 unregister_netdevice include/linux/netdevice.h:2715 [inline] __tun_detach+0xe4d/0x1120 drivers/net/tun.c:723 tun_detach drivers/net/tun.c:740 [inline] tun_chr_close+0xd9/0x180 drivers/net/tun.c:3459 __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: 0033:0x401170 Code: 01 f0 ff ff 0f 83 20 0c 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d 5d 25 2d 00 00 75 14 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 f4 0b 00 00 c3 48 83 ec 08 e8 5a 01 00 00 RSP: 002b:00007ffe3ff4f878 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000401170 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000001e71e0 R08: 0000000100000000 R09: 0000000100000000 R10: 0000000100000000 R11: 0000000000000246 R12: 00000000004021f0 R13: 0000000000402280 R14: 0000000000000000 R15: 0000000000000000