[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.098379] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.056168] random: sshd: uninitialized urandom read (32 bytes read) [ 23.339060] random: sshd: uninitialized urandom read (32 bytes read) [ 24.090819] random: sshd: uninitialized urandom read (32 bytes read) [ 36.388540] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.57' (ECDSA) to the list of known hosts. [ 41.934468] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 42.025462] WARNING: CPU: 1 PID: 4505 at net/ipv4/tcp_input.c:2212 tcp_mark_head_lost+0x8ee/0xa70 [ 42.034594] Kernel panic - not syncing: panic_on_warn set ... [ 42.034594] [ 42.041948] CPU: 1 PID: 4505 Comm: syz-executor340 Not tainted 4.17.0-rc2+ #31 [ 42.049297] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.058637] Call Trace: [ 42.061215] dump_stack+0x1b9/0x294 [ 42.064826] ? dump_stack_print_info.cold.2+0x52/0x52 [ 42.070003] ? tcp_mark_head_lost+0x8b0/0xa70 [ 42.074488] panic+0x22f/0x4de [ 42.077669] ? add_taint.cold.5+0x16/0x16 [ 42.081799] ? __warn.cold.8+0x148/0x1b3 [ 42.085842] ? __warn.cold.8+0x117/0x1b3 [ 42.089887] ? tcp_mark_head_lost+0x8ee/0xa70 [ 42.094369] __warn.cold.8+0x163/0x1b3 [ 42.098246] ? tcp_mark_head_lost+0x8ee/0xa70 [ 42.102727] report_bug+0x252/0x2d0 [ 42.106339] do_error_trap+0x1de/0x490 [ 42.110209] ? math_error+0x420/0x420 [ 42.113997] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 42.119516] ? tcp_rate_skb_delivered+0x2d0/0x3a0 [ 42.124346] ? tcp_sacktag_walk+0xc5d/0x14a0 [ 42.128743] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 42.133757] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.138596] do_invalid_op+0x1b/0x20 [ 42.142297] invalid_op+0x14/0x20 [ 42.145735] RIP: 0010:tcp_mark_head_lost+0x8ee/0xa70 [ 42.150817] RSP: 0018:ffff8801d96970b0 EFLAGS: 00010293 [ 42.156163] RAX: ffff8801acd82500 RBX: 0000000000000008 RCX: ffffffff864ab53c [ 42.163413] RDX: 0000000000000000 RSI: ffffffff864ab63e RDI: 0000000000000004 [ 42.170667] RBP: ffff8801d9697138 R08: ffff8801acd82500 R09: ffff8801d96974e8 [ 42.177920] R10: 0000000002814086 R11: ffff88021fff8057 R12: 0000000000000007 [ 42.185189] R13: ffff8801c52d4100 R14: dffffc0000000000 R15: 0000000000000005 [ 42.192452] ? tcp_mark_head_lost+0x7ec/0xa70 [ 42.196932] ? tcp_mark_head_lost+0x8ee/0xa70 [ 42.201422] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 42.206962] tcp_fastretrans_alert+0x1ff8/0x2850 [ 42.211703] tcp_ack+0x2c48/0x5510 [ 42.215234] ? tcp_fastretrans_alert+0x2850/0x2850 [ 42.220149] ? skb_scrub_packet+0x580/0x580 [ 42.224453] ? graph_lock+0x170/0x170 [ 42.228236] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 42.233755] ? ipv4_mtu+0x375/0x580 [ 42.237363] ? kasan_check_write+0x14/0x20 [ 42.241582] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 42.247102] ? tcp_established_options+0x36b/0x5a0 [ 42.252014] ? tcp_select_initial_window+0x3a0/0x3a0 [ 42.257106] ? graph_lock+0x170/0x170 [ 42.260890] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 42.266409] ? tcp_parse_options+0x1c1/0xe30 [ 42.270804] ? sched_clock_cpu+0x1b/0x180 [ 42.274935] tcp_rcv_established+0x5b1/0x2010 [ 42.279418] ? tcp_data_queue+0x45e0/0x45e0 [ 42.283726] ? lock_downgrade+0x8e0/0x8e0 [ 42.287859] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 42.292855] ? ipv4_dst_check+0x1d5/0x260 [ 42.296986] ? ipv4_sysctl_rtcache_flush+0xa0/0xa0 [ 42.301901] ? __local_bh_enable_ip+0x161/0x230 [ 42.306557] tcp_v4_do_rcv+0x615/0x8c0 [ 42.310429] __release_sock+0x12f/0x3a0 [ 42.314386] release_sock+0xa4/0x2b0 [ 42.318082] ? __release_sock+0x3a0/0x3a0 [ 42.322212] ? __local_bh_enable_ip+0x161/0x230 [ 42.326863] ? lock_sock_nested+0xe7/0x120 [ 42.331081] tcp_sendmsg+0x3a/0x50 [ 42.334604] inet_sendmsg+0x19f/0x690 [ 42.338385] ? ipip_gro_receive+0x100/0x100 [ 42.342695] ? security_socket_sendmsg+0x94/0xc0 [ 42.347437] ? ipip_gro_receive+0x100/0x100 [ 42.351758] sock_sendmsg+0xd5/0x120 [ 42.355480] sock_write_iter+0x35a/0x5a0 [ 42.359529] ? sock_sendmsg+0x120/0x120 [ 42.363495] ? __might_sleep+0x95/0x190 [ 42.367453] do_iter_readv_writev+0x859/0xa50 [ 42.371934] ? vfs_dedupe_file_range+0xa00/0xa00 [ 42.376672] ? rw_verify_area+0x118/0x360 [ 42.380801] do_iter_write+0x185/0x5f0 [ 42.384671] ? dup_iter+0x270/0x270 [ 42.388277] ? vfs_writev+0x255/0x330 [ 42.392075] vfs_writev+0x1c7/0x330 [ 42.395708] ? vfs_iter_write+0xb0/0xb0 [ 42.399665] ? lock_downgrade+0x8e0/0x8e0 [ 42.403796] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 42.409317] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 42.414832] ? __fdget_pos+0xd6/0x1e0 [ 42.418612] ? __fdget_raw+0x20/0x20 [ 42.422312] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 42.427833] ? __sys_setsockopt+0x24f/0x390 [ 42.432136] do_writev+0x112/0x2f0 [ 42.435662] ? vfs_writev+0x330/0x330 [ 42.439445] ? __ia32_sys_fallocate+0xf0/0xf0 [ 42.443929] __x64_sys_writev+0x75/0xb0 [ 42.447889] do_syscall_64+0x1b1/0x800 [ 42.451763] ? syscall_return_slowpath+0x5c0/0x5c0 [ 42.456674] ? syscall_return_slowpath+0x30f/0x5c0 [ 42.461587] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 42.466937] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.471762] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 42.476935] RIP: 0033:0x440219 [ 42.480371] RSP: 002b:00007ffc05b87b98 EFLAGS: 00000217 ORIG_RAX: 0000000000000014 [ 42.488061] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440219 [ 42.495311] RDX: 0000000000000001 RSI: 00000000200006c0 RDI: 0000000000000003 [ 42.502561] RBP: 00000000006cb018 R08: 0000000000000010 R09: 0000000000000010 [ 42.509814] R10: 0000000000000008 R11: 0000000000000217 R12: 0000000000401b40 [ 42.517064] R13: 0000000000401bd0 R14: 0000000000000000 R15: 0000000000000000 [ 42.524868] Dumping ftrace buffer: [ 42.528485] (ftrace buffer empty) [ 42.532192] Kernel Offset: disabled [ 42.535803] Rebooting in 86400 seconds..