Warning: Permanently added '10.128.0.45' (ECDSA) to the list of known hosts. executing program [ 42.567633] netlink: 8 bytes leftover after parsing attributes in process `syz-executor966'. [ 42.603189] [ 42.604818] =============================== [ 42.609112] [ INFO: suspicious RCU usage. ] [ 42.613440] 4.9.141+ #1 Not tainted [ 42.617091] ------------------------------- [ 42.621448] net/ipv6/ip6_fib.c:1471 suspicious rcu_dereference_protected() usage! [ 42.629080] [ 42.629080] other info that might help us debug this: [ 42.629080] [ 42.637341] [ 42.637341] rcu_scheduler_active = 2, debug_locks = 0 [ 42.644011] 4 locks held by syz-executor966/2056: [ 42.648836] #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 42.657243] #1: (&(&net->ipv6.fib6_gc_lock)->rlock){+.-...}, at: [] fib6_run_gc+0x226/0x2c0 [ 42.667989] #2: (rcu_read_lock){......}, at: [] __fib6_clean_all+0x0/0x220 [ 42.677301] #3: (&tb->tb6_lock){++-...}, at: [] __fib6_clean_all+0xe0/0x220 [ 42.686633] [ 42.686633] stack backtrace: [ 42.691111] CPU: 0 PID: 2056 Comm: syz-executor966 Not tainted 4.9.141+ #1 [ 42.698097] ffff8801ce99f448 ffffffff81b42e79 ffff8801cfc417c0 0000000000000000 [ 42.706144] 0000000000000002 ffffffff82cc2480 ffffed0039d33ed7 ffff8801ce99f478 [ 42.714131] ffffffff813fe948 ffff8801d65b28c0 ffff8801ce99f668 ffff8801d65b28c0 [ 42.722121] Call Trace: [ 42.724684] [] dump_stack+0xc1/0x128 [ 42.730146] [] lockdep_rcu_suspicious.cold.32+0x110/0x141 [ 42.737313] [] fib6_del+0x810/0xb10 [ 42.742564] [] ? kasan_slab_free+0x119/0x190 [ 42.748599] [] ? fib6_age+0x107/0x380 [ 42.754023] [] fib6_clean_node+0x220/0x4c0 [ 42.759882] [] ? fib6_del+0xb10/0xb10 [ 42.765314] [] ? __local_bh_enable_ip+0x6a/0xe0 [ 42.771611] [] ? trace_hardirqs_on_caller+0x266/0x590 [ 42.778435] [] ? fib6_walker_link+0xf6/0x140 [ 42.784593] [] fib6_walk_continue+0x3e5/0x640 [ 42.790721] [] ? fib6_flush_trees+0xc0/0xc0 [ 42.796681] [] fib6_walk+0x91/0xf0 [ 42.801925] [] fib6_clean_tree+0xd3/0x110 [ 42.807709] [] ? fib6_walk+0xf0/0xf0 [ 42.813058] [] ? fib6_del+0xb10/0xb10 [ 42.818590] [] ? fib6_flush_trees+0xc0/0xc0 [ 42.824539] [] ? fib6_clean_tree+0x110/0x110 [ 42.830575] [] __fib6_clean_all+0xf9/0x220 [ 42.836435] [] ? fib6_clean_tree+0x110/0x110 [ 42.842468] [] ? fib6_flush_trees+0xc0/0xc0 [ 42.848414] [] fib6_run_gc+0x117/0x2c0 [ 42.853932] [] ? fib6_clean_all+0x30/0x30 [ 42.859711] [] ? neigh_ifdown+0x202/0x2a0 [ 42.865491] [] ndisc_netdev_event+0x2ac/0x350 [ 42.871615] [] notifier_call_chain+0xb4/0x1d0 [ 42.877732] [] raw_notifier_call_chain+0x2d/0x40 [ 42.884117] [] call_netdevice_notifiers_info+0x55/0x70 [ 42.891017] [] dev_close_many+0x2e4/0x6a0 [ 42.896796] [] ? __dev_close_many+0x270/0x270 [ 42.902922] [] rollback_registered_many+0x3ac/0xb50 [ 42.909567] [] ? free_netdev+0x300/0x300 [ 42.915255] [] ? _raw_spin_unlock+0x3f/0x50 [ 42.921202] [] ? __queue_work+0x3f1/0xf10 [ 42.926982] [] ? queue_delayed_work_on+0x83/0xb0 [ 42.933368] [] rollback_registered+0xee/0x1b0 [ 42.939489] [] ? rollback_registered_many+0xb50/0xb50 [ 42.946304] [] ? linkwatch_schedule_work+0x10c/0x130 [ 42.953047] [] unregister_netdevice_queue+0x1aa/0x230 [ 42.959985] [] __tun_detach+0x821/0xa00 [ 42.965593] [] ? __tun_detach+0xa00/0xa00 [ 42.971369] [] tun_chr_close+0x44/0x60 [ 42.976882] [] __fput+0x263/0x700 [ 42.981963] [] ____fput+0x15/0x20 [ 42.987159] [] task_work_run+0x10c/0x180 [ 42.992969] [] do_exit+0x78d/0x2a50 [ 42.998270] [] ? debug_lockdep_rcu_enabled.part.0+0x51/0x60 [ 43.005702] [] ? release_task.part.4+0x14b0/0x14b0 [ 43.012264] [] ? __do_page_fault+0x431/0xa60 [ 43.018303] [] ? up_read+0x1a/0x40 [ 43.023667] [] ? __do_page_fault+0x554/0xa60 [ 43.029706] [] do_group_exit+0x111/0x300 [ 43.035393] [] ? do_group_exit+0x300/0x300 [ 43.041254] [] SyS_exit_group+0x1d/0x20 [ 43.046850] [] do_syscall_64+0x19f/0x550 [ 43.052534] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb