[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.15.220' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 35.073491] [ 35.075160] ============================= [ 35.079524] WARNING: suspicious RCU usage [ 35.083655] 4.14.302-syzkaller #0 Not tainted [ 35.088257] ----------------------------- [ 35.092385] net/tipc/bearer.c:177 suspicious rcu_dereference_protected() usage! [ 35.100062] [ 35.100062] other info that might help us debug this: [ 35.100062] [ 35.108425] [ 35.108425] rcu_scheduler_active = 2, debug_locks = 1 [ 35.115072] 2 locks held by syz-executor207/7962: [ 35.119956] #0: (cb_lock){++++}, at: [] genl_rcv+0x15/0x40 [ 35.127400] #1: (genl_mutex){+.+.}, at: [] genl_rcv_msg+0x112/0x140 [ 35.135529] [ 35.135529] stack backtrace: [ 35.140063] CPU: 1 PID: 7962 Comm: syz-executor207 Not tainted 4.14.302-syzkaller #0 [ 35.147925] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 [ 35.157250] Call Trace: [ 35.159814] dump_stack+0x1b2/0x281 [ 35.163418] tipc_bearer_find+0x1ff/0x2f0 [ 35.167538] tipc_nl_compat_link_set+0x40b/0xb90 [ 35.172265] ? __alloc_skb+0x3dc/0x510 [ 35.176126] tipc_nl_compat_doit+0x192/0x5d0 [ 35.180505] ? tipc_nl_compat_link_set+0xb90/0xb90 [ 35.185408] ? security_capable+0x88/0xb0 [ 35.189535] ? ns_capable_common+0x127/0x150 [ 35.193915] tipc_nl_compat_recv+0xa0b/0xae0 [ 35.198296] ? tipc_nl_compat_dumpit+0x7a0/0x7a0 [ 35.203021] ? tipc_nl_node_dump+0xc20/0xc20 [ 35.207398] ? __tipc_add_link_prop.isra.0+0x190/0x190 [ 35.212645] ? lock_downgrade+0x740/0x740 [ 35.216771] genl_family_rcv_msg+0x572/0xb20 [ 35.221151] ? __lock_acquire+0x5fc/0x3f20 [ 35.225356] ? genl_rcv+0x40/0x40 [ 35.228782] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 35.234205] ? __kmalloc_node_track_caller+0x4c/0x70 [ 35.239281] ? trace_hardirqs_on+0x10/0x10 [ 35.243491] genl_rcv_msg+0xaf/0x140 [ 35.247176] netlink_rcv_skb+0x125/0x390 [ 35.251207] ? genl_family_rcv_msg+0xb20/0xb20 [ 35.255763] ? netlink_ack+0x9a0/0x9a0 [ 35.259621] ? lock_acquire+0x170/0x3f0 [ 35.263595] genl_rcv+0x24/0x40 [ 35.266849] netlink_unicast+0x437/0x610 [ 35.270883] ? netlink_sendskb+0xd0/0xd0 [ 35.274915] ? __check_object_size+0x179/0x230 [ 35.279468] netlink_sendmsg+0x648/0xbc0 [ 35.283514] ? nlmsg_notify+0x1b0/0x1b0 [ 35.287464] ? kernel_recvmsg+0x210/0x210 [ 35.291594] ? security_socket_sendmsg+0x83/0xb0 [ 35.296327] ? nlmsg_notify+0x1b0/0x1b0 [ 35.300281] sock_sendmsg+0xb5/0x100 [ 35.303975] ___sys_sendmsg+0x6c8/0x800 [ 35.307924] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 35.312657] ? __lock_acquire+0x5fc/0x3f20 [ 35.316869] ? __dentry_kill+0x3f7/0x550 [ 35.320905] ? trace_hardirqs_on+0x10/0x10 [ 35.325115] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 35.330536] ? dentry_free+0xc6/0x120 [ 35.334314] ? rcu_read_lock_sched_held+0x16c/0x1d0 [ 35.339314] ? kmem_cache_free+0x23a/0x2b0 [ 35.343549] ? mntput_no_expire+0xc7/0x910 [ 35.347762] ? lock_acquire+0x170/0x3f0 [ 35.351709] ? __fdget+0x167/0x1f0 [ 35.355223] ? sockfd_lookup_light+0xb2/0x160 [ 35.359693] __sys_sendmsg+0xa3/0x120 [ 35.363470] ? SyS_shutdown+0x160/0x160 [ 35.367423] SyS_sendmsg+0x27/0x40 [ 35.370934] ? __sys_sendmsg+0x120/0x120 [ 35.374966] do_syscall_64+0x1d5/0x640 [ 35.378830] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 35.383992] RIP: 0033:0x7f9a6f5eab69 [ 35.387675] RSP: 002b:00007ffe0e22ebf8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 35.395354] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9a6f5eab69 [ 35.402596] RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000003 [ 35.409839] RBP: 00007f9a6f5ae5d0 R08: 0000000000000000 R09: 0000000000000000 [ 35.417295] R10: 0000000000001800 R11: 0000000000000246 R12: 00007f9a6f5ae660 [ 35.4