BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! turning off the locking correctness validator. CPU: 1 PID: 20388 Comm: syz-executor.1 Not tainted 5.6.0-rc7-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:4162 [inline] dev_uc_flush+0x19/0x30 net/core/dev_addr_lists.c:710 rollback_registered_many+0x801/0xe70 net/core/dev.c:8820 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_32_irqs_on arch/x86/entry/common.c:352 [inline] do_fast_syscall_32+0xbef/0xe8f arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139