[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.13' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 28.766427] [ 28.768110] ============================= [ 28.773060] WARNING: suspicious RCU usage [ 28.777206] 4.14.302-syzkaller #0 Not tainted [ 28.782310] ----------------------------- [ 28.786443] net/tipc/bearer.c:177 suspicious rcu_dereference_protected() usage! [ 28.794198] [ 28.794198] other info that might help us debug this: [ 28.794198] [ 28.802985] [ 28.802985] rcu_scheduler_active = 2, debug_locks = 1 [ 28.809917] 2 locks held by syz-executor342/7977: [ 28.814752] #0: (cb_lock){++++}, at: [] genl_rcv+0x15/0x40 [ 28.822210] #1: (genl_mutex){+.+.}, at: [] genl_rcv_msg+0x112/0x140 [ 28.830464] [ 28.830464] stack backtrace: [ 28.834956] CPU: 0 PID: 7977 Comm: syz-executor342 Not tainted 4.14.302-syzkaller #0 [ 28.842817] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 [ 28.852154] Call Trace: [ 28.854722] dump_stack+0x1b2/0x281 [ 28.858327] tipc_bearer_find+0x1ff/0x2f0 [ 28.862453] tipc_nl_compat_link_set+0x40b/0xb90 [ 28.867182] ? __alloc_skb+0x3dc/0x510 [ 28.871052] tipc_nl_compat_doit+0x192/0x5d0 [ 28.875455] ? tipc_nl_compat_link_set+0xb90/0xb90 [ 28.880364] ? security_capable+0x88/0xb0 [ 28.884489] ? ns_capable_common+0x127/0x150 [ 28.888875] tipc_nl_compat_recv+0xa0b/0xae0 [ 28.893260] ? tipc_nl_compat_dumpit+0x7a0/0x7a0 [ 28.898006] ? tipc_nl_node_dump+0xc20/0xc20 [ 28.902858] ? __tipc_add_link_prop.isra.0+0x190/0x190 [ 28.909419] ? lock_downgrade+0x740/0x740 [ 28.913559] genl_family_rcv_msg+0x572/0xb20 [ 28.917950] ? __lock_acquire+0x5fc/0x3f20 [ 28.922271] ? genl_rcv+0x40/0x40 [ 28.925708] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 28.931161] ? __kmalloc_node_track_caller+0x4c/0x70 [ 28.936246] ? trace_hardirqs_on+0x10/0x10 [ 28.940461] genl_rcv_msg+0xaf/0x140 [ 28.944152] netlink_rcv_skb+0x125/0x390 [ 28.948187] ? genl_family_rcv_msg+0xb20/0xb20 [ 28.952745] ? netlink_ack+0x9a0/0x9a0 [ 28.956607] ? lock_acquire+0x170/0x3f0 [ 28.960561] genl_rcv+0x24/0x40 [ 28.963816] netlink_unicast+0x437/0x610 [ 28.967867] ? netlink_sendskb+0xd0/0xd0 [ 28.971919] ? __check_object_size+0x179/0x230 [ 28.976488] netlink_sendmsg+0x648/0xbc0 [ 28.980531] ? nlmsg_notify+0x1b0/0x1b0 [ 28.984482] ? kernel_recvmsg+0x210/0x210 [ 28.988609] ? security_socket_sendmsg+0x83/0xb0 [ 28.993339] ? nlmsg_notify+0x1b0/0x1b0 [ 28.997285] sock_sendmsg+0xb5/0x100 [ 29.000997] ___sys_sendmsg+0x6c8/0x800 [ 29.004962] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 29.009698] ? __lock_acquire+0x5fc/0x3f20 [ 29.013912] ? __dentry_kill+0x3f7/0x550 [ 29.017947] ? trace_hardirqs_on+0x10/0x10 [ 29.022158] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 29.027585] ? dentry_free+0xc6/0x120 [ 29.031381] ? rcu_read_lock_sched_held+0x16c/0x1d0 [ 29.036390] ? kmem_cache_free+0x23a/0x2b0 [ 29.040605] ? mntput_no_expire+0xc7/0x910 [ 29.044817] ? lock_acquire+0x170/0x3f0 [ 29.048765] ? __fdget+0x167/0x1f0 [ 29.052313] ? sockfd_lookup_light+0xb2/0x160 [ 29.056884] __sys_sendmsg+0xa3/0x120 [ 29.060666] ? SyS_shutdown+0x160/0x160 [ 29.064620] SyS_sendmsg+0x27/0x40 [ 29.068133] ? __sys_sendmsg+0x120/0x120 [ 29.072169] do_syscall_64+0x1d5/0x640 [ 29.076138] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 29.081320] RIP: 0033:0x7f3ccaa67b69 [ 29.085004] RSP: 002b:00007fffe4221638 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 29.092686] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3ccaa67b69 [ 29.100017] RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000003 [ 29.107263] RBP: 00007f3ccaa2b5d0 R08: 0000000000000000 R09: 0000000000000000 [ 29.114508] R10: 0000000000001800 R11: