Warning: Permanently added '10.128.1.41' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 31.587358] [ 31.589070] ============================= [ 31.593941] WARNING: suspicious RCU usage [ 31.598092] 4.14.214-syzkaller #0 Not tainted [ 31.603683] ----------------------------- [ 31.607861] net/tipc/bearer.c:177 suspicious rcu_dereference_protected() usage! [ 31.616042] [ 31.616042] other info that might help us debug this: [ 31.616042] [ 31.624952] [ 31.624952] rcu_scheduler_active = 2, debug_locks = 1 [ 31.631620] 2 locks held by syz-executor976/7985: [ 31.637146] #0: (cb_lock){++++}, at: [] genl_rcv+0x15/0x40 [ 31.644957] #1: (genl_mutex){+.+.}, at: [] genl_rcv_msg+0x112/0x140 [ 31.653611] [ 31.653611] stack backtrace: [ 31.658123] CPU: 1 PID: 7985 Comm: syz-executor976 Not tainted 4.14.214-syzkaller #0 [ 31.665995] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.675328] Call Trace: [ 31.677899] dump_stack+0x1b2/0x283 [ 31.681506] tipc_bearer_find+0x1ff/0x2f0 [ 31.685642] tipc_nl_compat_link_set+0x40b/0xb90 [ 31.690375] ? __alloc_skb+0x3dc/0x510 [ 31.694244] tipc_nl_compat_doit+0x192/0x5d0 [ 31.698640] ? tipc_nl_compat_link_set+0xb90/0xb90 [ 31.703555] ? security_capable+0x88/0xb0 [ 31.707696] ? ns_capable_common+0x127/0x150 [ 31.712089] tipc_nl_compat_recv+0xa0b/0xae0 [ 31.716478] ? tipc_nl_compat_dumpit+0x7a0/0x7a0 [ 31.721211] ? tipc_nl_node_dump+0xc20/0xc20 [ 31.725594] ? __tipc_add_link_prop.isra.0+0x190/0x190 [ 31.730864] ? lock_downgrade+0x740/0x740 [ 31.734996] genl_family_rcv_msg+0x572/0xb20 [ 31.739380] ? __lock_acquire+0x5fc/0x3f20 [ 31.743589] ? genl_rcv+0x40/0x40 [ 31.747016] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 31.752444] ? trace_hardirqs_on+0x10/0x10 [ 31.756658] ? sock_sendmsg+0xb5/0x100 [ 31.760536] genl_rcv_msg+0xaf/0x140 [ 31.764227] netlink_rcv_skb+0x125/0x390 [ 31.768263] ? genl_family_rcv_msg+0xb20/0xb20 [ 31.772834] ? netlink_ack+0x9a0/0x9a0 [ 31.776707] ? lock_acquire+0x170/0x3f0 [ 31.780711] genl_rcv+0x24/0x40 [ 31.783973] netlink_unicast+0x437/0x610 [ 31.788025] ? netlink_sendskb+0xd0/0xd0 [ 31.792063] ? __check_object_size+0x179/0x22c [ 31.796620] netlink_sendmsg+0x62e/0xb80 [ 31.800681] ? nlmsg_notify+0x170/0x170 [ 31.804637] ? kernel_recvmsg+0x210/0x210 [ 31.808766] ? security_socket_sendmsg+0x83/0xb0 [ 31.813535] ? nlmsg_notify+0x170/0x170 [ 31.817486] sock_sendmsg+0xb5/0x100 [ 31.821234] ___sys_sendmsg+0x6c8/0x800 [ 31.825190] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 31.829922] ? trace_hardirqs_on+0x10/0x10 [ 31.834133] ? trace_hardirqs_on+0x10/0x10 [ 31.838356] ? apparmor_file_alloc_security+0x129/0x800 [ 31.843697] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 31.849135] ? __lockdep_init_map+0x100/0x560 [ 31.853617] ? __fd_install+0x1ec/0x5c0 [ 31.857565] ? lock_acquire+0x170/0x3f0 [ 31.861532] ? lock_downgrade+0x740/0x740 [ 31.865661] ? __fdget+0x167/0x1f0 [ 31.869176] ? sockfd_lookup_light+0xb2/0x160 [ 31.873660] __sys_sendmsg+0xa3/0x120 [ 31.877455] ? SyS_shutdown+0x160/0x160 [ 31.881439] ? move_addr_to_kernel+0x60/0x60 [ 31.885831] SyS_sendmsg+0x27/0x40 [ 31.889344] ? __sys_sendmsg+0x120/0x120 [ 31.893389] do_syscall_64+0x1d5/0x640 [ 31.897259] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.902424] RIP: 0033:0x440979 [ 31.905587] RSP: 002b:00007ffe5b87ebb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 31.913272] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440979 [ 31.920539] RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003 [ 31.927802] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 31.935058] R10: 0000000000001800 R11: 0000