[ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.203' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 66.859038][ T6560] [ 66.861468][ T6560] ============================= [ 66.866296][ T6560] WARNING: suspicious RCU usage [ 66.871783][ T6560] 5.15.0-rc2-next-20210920-syzkaller #0 Not tainted [ 66.878664][ T6560] ----------------------------- [ 66.883548][ T6560] net/xfrm/xfrm_user.c:1157 suspicious rcu_dereference_check() usage! [ 66.891872][ T6560] [ 66.891872][ T6560] other info that might help us debug this: [ 66.891872][ T6560] [ 66.902178][ T6560] [ 66.902178][ T6560] rcu_scheduler_active = 2, debug_locks = 1 [ 66.910330][ T6560] 1 lock held by syz-executor917/6560: [ 66.915961][ T6560] #0: ffffffff8d0d4818 (&net->xfrm.xfrm_cfg_mutex){+.+.}-{3:3}, at: xfrm_netlink_rcv+0x5c/0x90 [ 66.926573][ T6560] [ 66.926573][ T6560] stack backtrace: [ 66.932643][ T6560] CPU: 0 PID: 6560 Comm: syz-executor917 Not tainted 5.15.0-rc2-next-20210920-syzkaller #0 [ 66.942616][ T6560] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.952663][ T6560] Call Trace: [ 66.955941][ T6560] dump_stack_lvl+0xcd/0x134 [ 66.960543][ T6560] xfrm_set_default+0x789/0x8b0 [ 66.965388][ T6560] ? xfrm_send_mapping+0x810/0x810 [ 66.970495][ T6560] xfrm_user_rcv_msg+0x430/0xa20 [ 66.975439][ T6560] ? xfrm_do_migrate+0x7f0/0x7f0 [ 66.980371][ T6560] ? lock_chain_count+0x20/0x20 [ 66.985223][ T6560] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 66.991229][ T6560] ? __mutex_lock+0x21c/0x12f0 [ 66.995991][ T6560] netlink_rcv_skb+0x153/0x420 [ 67.000939][ T6560] ? xfrm_do_migrate+0x7f0/0x7f0 [ 67.005891][ T6560] ? netlink_ack+0xa60/0xa60 [ 67.010489][ T6560] ? netlink_deliver_tap+0x1b1/0xc30 [ 67.015864][ T6560] ? _copy_from_iter+0x12b/0x1320 [ 67.021075][ T6560] xfrm_netlink_rcv+0x6b/0x90 [ 67.025851][ T6560] netlink_unicast+0x533/0x7d0 [ 67.030621][ T6560] ? netlink_attachskb+0x890/0x890 [ 67.035728][ T6560] ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70 [ 67.041983][ T6560] ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70 [ 67.048218][ T6560] ? __phys_addr_symbol+0x2c/0x70 [ 67.053236][ T6560] ? __sanitizer_cov_trace_cmp8+0x1d/0x70 [ 67.058948][ T6560] ? __check_object_size+0x16e/0x3f0 [ 67.064246][ T6560] netlink_sendmsg+0x86d/0xdb0 [ 67.069023][ T6560] ? netlink_unicast+0x7d0/0x7d0 [ 67.073967][ T6560] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 67.080213][ T6560] ? netlink_unicast+0x7d0/0x7d0 [ 67.085157][ T6560] sock_sendmsg+0xcf/0x120 [ 67.089586][ T6560] ____sys_sendmsg+0x6e8/0x810 [ 67.094386][ T6560] ? kernel_sendmsg+0x50/0x50 [ 67.099061][ T6560] ? do_recvmmsg+0x6d0/0x6d0 [ 67.103648][ T6560] ? do_huge_pmd_anonymous_page+0x12c4/0x2840 [ 67.109811][ T6560] ? lock_downgrade+0x6e0/0x6e0 [ 67.114662][ T6560] ___sys_sendmsg+0xf3/0x170 [ 67.119256][ T6560] ? sendmsg_copy_msghdr+0x160/0x160 [ 67.124546][ T6560] ? __lock_acquire+0x162f/0x54a0 [ 67.129576][ T6560] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 67.135552][ T6560] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 67.141532][ T6560] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 67.147779][ T6560] ? __fget_light+0x215/0x280 [ 67.152451][ T6560] ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70 [ 67.158688][ T6560] __sys_sendmsg+0xe5/0x1b0 [ 67.163189][ T6560] ? __sys_sendmsg_sock+0x30/0x30 [ 67.168229][ T6560] ? syscall_enter_from_user_mode+0x21/0x70 [ 67.174124][ T6560] do_syscall_64+0x35/0xb0 [ 67.178545][ T6560] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 67.184437][ T6560] RIP: 0033:0x7fe115dcd079 [ 67.188846][ T6560] Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 [ 67.208444][ T6560] RSP: 002b:00007ffedbf3ee68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 67.216849][ T6560] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe115dcd079 [ 67.224821][ T6560] RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000003 [ 67.232890][ T6560] RBP: 00007fe115d91060 R08: 0000000000000000 R09: 0000000000000000 [ 67.240863][ T6560] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe115d910f0 [ 67.248826][ T6560] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 67.257144][ T6560] unsupported nlmsg_t