[....] Starting enhanced syslogd: rsyslogd[ 13.479629] audit: type=1400 audit(1571988387.365:4): avc: denied { syslog } for pid=1917 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.208' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 25.363498] ------------[ cut here ]------------ [ 25.368296] kernel BUG at net/ipv4/tcp_input.c:4839! [ 25.373398] invalid opcode: 0000 [#1] PREEMPT SMP KASAN [ 25.379263] Modules linked in: [ 25.382583] CPU: 0 PID: 2219 Comm: syz-executor442 Not tainted 4.4.174+ #17 [ 25.389668] task: ffff8801d3cd2f80 task.stack: ffff8801d3788000 [ 25.395706] RIP: 0010:[] [] tcp_collapse+0x9bd/0xda0 [ 25.404143] RSP: 0018:ffff8801db6073c8 EFLAGS: 00010206 [ 25.409578] RAX: ffff8801d3cd2f80 RBX: 0000000000000450 RCX: 000000000a40b7bb [ 25.416836] RDX: 0000000000000100 RSI: ffffffff824121bd RDI: 0000000000000450 [ 25.424092] RBP: ffff8801db607518 R08: 1ffff10016ea6ecd R09: ffffed0016ea6ed3 [ 25.431359] R10: ffffed0016ea6ed2 R11: ffff8800b7537697 R12: ffff8801d2c0d78c [ 25.438619] R13: ffff8801d2c0d760 R14: dffffc0000000000 R15: ffff8800b7537640 [ 25.445874] FS: 0000000000000000(0000) GS:ffff8801db600000(0063) knlGS:00000000f77cdb40 [ 25.454086] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 25.459954] CR2: 0000000000000000 CR3: 00000001cef42000 CR4: 00000000001606b0 [ 25.467233] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 25.474486] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 25.481739] Stack: [ 25.483871] ffff8800b8722a40 ffffed00170e4548 ffff8800b753766c ffff8801db607460 [ 25.491903] ffff8801d3725680 ffff880000000900 0000000000000000 ffff8800b8722900 [ 25.499961] 1ffff1003b6c0e86 0000000000000000 fffffc1800000450 ffff8800b8722a30 [ 25.508006] Call Trace: [ 25.510569] [ 25.512629] [] ? tcp_rearm_rto.part.0+0x270/0x270 [ 25.519409] [] ? tcp_xmit_retransmit_queue+0x5cf/0xb90 [ 25.526319] [] ? check_preemption_disabled+0x3c/0x200 [ 25.533143] [] tcp_try_rmem_schedule+0x6ba/0x1280 [ 25.539624] [] tcp_data_queue+0x11f2/0x3a90 [ 25.545580] [] ? tcp_rcv_space_adjust+0x450/0x450 [ 25.552072] [] ? tcp_send_challenge_ack.isra.0+0x160/0x1b0 [ 25.559335] [] ? tcp_validate_incoming+0x3b1/0xf90 [ 25.565907] [] tcp_rcv_established+0x599/0x2070 [ 25.572212] [] ? sk_filter_trim_cap+0x3de/0x6d0 [ 25.578518] [] ? tcp_validate_incoming+0xf90/0xf90 [ 25.585079] [] ? sk_filter_trim_cap+0xd7/0x6d0 [ 25.591291] [] ? sk_filter_trim_cap+0x11a/0x6d0 [ 25.597600] [] tcp_v4_do_rcv+0x553/0x7a0 [ 25.603292] [] tcp_prequeue+0x4dd/0xdc0 [ 25.608902] [] tcp_v4_rcv+0x29a3/0x36b0 [ 25.614512] [] ip_local_deliver_finish+0x3c0/0xa70 [ 25.621075] [] ? ip_local_deliver_finish+0x12a/0xa70 [ 25.627815] [] ip_local_deliver+0x1af/0x390 [ 25.633771] [] ? ip_call_ra_chain+0x540/0x540 [ 25.639903] [] ? nf_hook_slow+0x1dc/0x340 [ 25.645683] [] ? inet_del_offload+0x40/0x40 [ 25.651639] [] ? nf_hook_slow+0x203/0x340 [ 25.657426] [] ? nf_iterate+0x220/0x220 [ 25.663036] [] ip_rcv_finish+0x768/0x1220 [ 25.668815] [] ip_rcv+0x8fa/0xe70 [ 25.673904] [] ? ip_local_deliver+0x390/0x390 [ 25.680033] [] ? ip_local_deliver_finish+0xa70/0xa70 [ 25.686771] [] ? ip_local_deliver+0x390/0x390 [ 25.692918] [] __netif_receive_skb_core+0x1300/0x2950 [ 25.699746] [] ? dev_loopback_xmit+0x430/0x430 [ 25.705962] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 25.712713] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 25.719454] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 25.726193] [] ? check_preemption_disabled+0x3c/0x200 [ 25.733104] [] __netif_receive_skb+0x58/0x1c0 [ 25.739237] [] process_backlog+0x200/0x630 [ 25.745112] [] ? process_backlog+0x19c/0x630 [ 25.751158] [] ? net_rx_action+0x1fb/0xd30 [ 25.757025] [] net_rx_action+0x367/0xd30 [ 25.762720] [] ? net_rps_action_and_irq_enable.isra.0+0x170/0x170 [ 25.770592] [] __do_softirq+0x226/0xa3f [ 25.776209] [] ? release_sock+0x3a8/0x500 [ 25.782006] [] do_softirq_own_stack+0x1c/0x30 [ 25.788128] [ 25.790177] [] do_softirq.part.0+0x54/0x60 [ 25.796346] [] __local_bh_enable_ip+0xcc/0xe0 [ 25.802478] [] _raw_spin_unlock_bh+0x31/0x40 [ 25.808520] [] release_sock+0x3a8/0x500 [ 25.814126] [] sk_wait_data+0x138/0x3b0 [ 25.819734] [] ? mark_held_locks+0xb1/0x100 [ 25.825688] [] ? release_sock+0x500/0x500 [ 25.831473] [] ? autoremove_wake_function.part.0+0x130/0x130 [ 25.838917] [] ? __local_bh_enable_ip+0x6a/0xe0 [ 25.845219] [] ? tcp_prequeue_process+0x20e/0x360 [ 25.851698] [] tcp_recvmsg+0xfb6/0x2d10 [ 25.857307] [] ? tcp_tx_timestamp.part.0+0x230/0x230 [ 25.864044] [] ? check_preemption_disabled+0x3c/0x200 [ 25.870865] [] ? check_preemption_disabled+0x3c/0x200 [ 25.877690] [] ? inet_recvmsg+0x1a8/0x4d0 [ 25.883472] [] inet_recvmsg+0x23e/0x4d0 [ 25.889082] [] ? inet_recvmsg+0xda/0x4d0 [ 25.894791] [] ? dup_iter+0x290/0x290 [ 25.900239] [] ? inet_stream_connect+0xa0/0xa0 [ 25.906467] [] ? selinux_socket_recvmsg+0x3f/0x50 [ 25.912947] [] ? security_socket_recvmsg+0x97/0xc0 [ 25.919511] [] sock_recvmsg+0x8f/0xc0 [ 25.924945] [] ? __sock_recv_ts_and_drops+0x380/0x380 [ 25.931768] [] ___sys_recvmsg+0x257/0x530 [ 25.937550] [] ? trace_hardirqs_on+0x10/0x10 [ 25.943593] [] ? ___sys_sendmsg+0x890/0x890 [ 25.949550] [] ? check_preemption_disabled+0x3c/0x200 [ 25.956373] [] ? check_preemption_disabled+0x3c/0x200 [ 25.963198] [] ? __fget+0x13b/0x370 [ 25.968462] [] ? __fget+0x162/0x370 [ 25.973722] [] ? __fget+0x47/0x370 [ 25.978896] [] ? __fget_light+0xa3/0x1f0 [ 25.984591] [] ? __fdget+0x1b/0x20 [ 25.990736] [] ? sockfd_lookup_light+0xb4/0x160 [ 25.997039] [] __sys_recvmsg+0xc5/0x160 [ 26.002646] [] ? SyS_sendmmsg+0x60/0x60 [ 26.008267] [] ? __do_page_fault+0x2b3/0x7f0 [ 26.014320] [] compat_SyS_recvmsg+0x2a/0x40 [ 26.020285] [] ? compat_SyS_sendmmsg+0x40/0x40 [ 26.026505] [] do_fast_syscall_32+0x32d/0xa90 [ 26.032636] [] sysenter_flags_fixed+0xd/0x1a [ 26.038672] Code: 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 03 02 00 00 44 3b 73 28 79 a5 e8 3e 74 ef fe 4c 8d 7b 10 eb a3 e8 33 74 ef fe <0f> 0b e8 2c 74 ef fe 48 8b 8d e0 fe ff ff 4c 89 ee 48 8b 95 08 [ 26.066179] RIP [] tcp_collapse+0x9bd/0xda0 [ 26.072281] RSP [ 26.075950] ---[ end trace d4789cf5fd5835d7 ]--- [ 26.080712] Kernel panic - not syncing: Fatal exception in interrupt [ 26.087795] Kernel Offset: disabled [ 26.091406] Rebooting in 86400 seconds..