[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.124713] random: sshd: uninitialized urandom read (32 bytes read, 31 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.715893] random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available) [ 20.915555] random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available) [ 21.888055] random: sshd: uninitialized urandom read (32 bytes read, 103 bits of entropy available) [ 36.715064] random: sshd: uninitialized urandom read (32 bytes read, 115 bits of entropy available) Warning: Permanently added '10.128.0.11' (ECDSA) to the list of known hosts. [ 42.151595] random: sshd: uninitialized urandom read (32 bytes read, 121 bits of entropy available) executing program [ 42.243608] ------------[ cut here ]------------ [ 42.248394] WARNING: CPU: 1 PID: 3667 at net/core/skbuff.c:4183 skb_try_coalesce+0xfa6/0x15f0() [ 42.257319] Kernel panic - not syncing: panic_on_warn set ... [ 42.257319] [ 42.264666] CPU: 1 PID: 3667 Comm: syzkaller095651 Not tainted 4.4.120-gd63fdf6 #28 [ 42.272449] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.281783] 0000000000000000 86b1d0de4b52ce02 ffff8801db307228 ffffffff81d0408d [ 42.289758] ffffffff83843b40 ffff8801db307300 ffffffff83ca8de0 0000000000000009 [ 42.297738] 0000000000001057 ffff8801db3072f0 ffffffff8141ab2a 0000000041b58ab3 [ 42.305721] Call Trace: [ 42.308275] [] dump_stack+0xc1/0x124 [ 42.314347] [] panic+0x1aa/0x388 [ 42.320810] [] ? percpu_up_read.constprop.45+0xe1/0xe1 [ 42.327713] [] ? pm_qos_get_value.part.4+0xb/0xb [ 42.334101] [] ? tcp_ack+0x2138/0x4660 [ 42.339609] [] ? tcp_rcv_established+0x5ee/0x2230 [ 42.346078] [] ? tcp_v6_do_rcv+0x42d/0x1470 [ 42.352027] [] ? warn_slowpath_common+0x10a/0x140 [ 42.358504] [] warn_slowpath_common+0x125/0x140 [ 42.364803] [] ? skb_try_coalesce+0xfa6/0x15f0 [ 42.371002] [] warn_slowpath_null+0x29/0x30 [ 42.376940] [] skb_try_coalesce+0xfa6/0x15f0 [ 42.382968] [] tcp_try_coalesce+0x15c/0x4d0 [ 42.388920] [] ? tcp_parse_options+0x970/0x970 [ 42.395126] [] ? sk_reset_timer+0x37/0x40 [ 42.401006] [] tcp_queue_rcv+0x127/0x720 [ 42.407643] [] tcp_data_queue+0xd9b/0x48e0 [ 42.413502] [] ? tcp_rcv_space_adjust+0x400/0x400 [ 42.419981] [] ? tcp_sendpage+0x15d0/0x1830 [ 42.425926] [] ? tcp_send_challenge_ack.isra.51+0x1b0/0x1b0 [ 42.433351] [] ? tcp_validate_incoming+0x721/0xfa0 [ 42.439909] [] tcp_rcv_established+0x7ca/0x2230 [ 42.446198] [] ? rt6_check+0x114/0x250 [ 42.451702] [] ? tcp_validate_incoming+0xfa0/0xfa0 [ 42.458251] [] ? rt6_check+0x15b/0x250 [ 42.463757] [] ? ip6_mtu+0x340/0x340 [ 42.469089] [] ? ip6_dst_check+0x16e/0x2c0 [ 42.474948] [] tcp_v6_do_rcv+0x42d/0x1470 [ 42.480730] [] ? tcp_prequeue+0x5b0/0xe10 [ 42.486507] [] tcp_v6_rcv+0x1b8d/0x2800 [ 42.492101] [] ? raw6_local_deliver+0x452/0x7e0 [ 42.498390] [] ip6_input_finish+0x329/0x1540 [ 42.504416] [] ? ip6_rcv_finish+0x630/0x630 [ 42.510359] [] ip6_input+0x106/0x200 [ 42.515690] [] ? ipv6_rcv+0x1e60/0x1e60 [ 42.521287] [] ? ip6_rcv_finish+0x630/0x630 [ 42.527232] [] ? nf_iterate+0x220/0x220 [ 42.532829] [] ip6_rcv_finish+0x138/0x630 [ 42.538593] [] ipv6_rcv+0x1055/0x1e60 [ 42.544012] [] ? ipv6_rcv+0xf7/0x1e60 [ 42.549433] [] ? ip6_input_finish+0x1540/0x1540 [ 42.555733] [] ? ip6_make_skb+0x3f0/0x3f0 [ 42.561501] [] ? ip6_input_finish+0x1540/0x1540 [ 42.567795] [] __netif_receive_skb_core+0xa59/0x28f0 [ 42.574532] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 42.581534] [] ? kmem_cache_free+0xc7/0x320 [ 42.587475] [] ? file_free_rcu+0x54/0x70 [ 42.593161] [] ? rcu_process_callbacks+0x7f4/0x14a0 [ 42.599812] [] ? dev_cpu_callback+0x670/0x670 [ 42.605930] [] ? do_sys_ftruncate.constprop.13+0x3c4/0x520 [ 42.613173] [] ? SyS_ftruncate+0x1c/0x30 [ 42.618854] [] ? entry_SYSCALL_64_fastpath+0x1c/0x98 [ 42.625578] [] ? check_preemption_disabled+0x3b/0x200 [ 42.632388] [] __netif_receive_skb+0x5b/0x1c0 [ 42.638505] [] process_backlog+0x213/0x690 [ 42.644360] [] ? process_backlog+0x1af/0x690 [ 42.650389] [] net_rx_action+0x373/0xe70 [ 42.656070] [] ? napi_complete_done+0x1f0/0x1f0 [ 42.662359] [] ? __lock_is_held+0xa1/0xf0 [ 42.668126] [] ? check_preemption_disabled+0x3b/0x200 [ 42.674935] [] ? check_preemption_disabled+0x3b/0x200 [ 42.681756] [] __do_softirq+0x227/0xa38 [ 42.687348] [] ? release_sock+0x3be/0x510 [ 42.693117] [] do_softirq_own_stack+0x1c/0x30 [ 42.699238] [] do_softirq.part.17+0x54/0x60 [ 42.705915] [] __local_bh_enable_ip+0xbe/0xd0 [ 42.712031] [] _raw_spin_unlock_bh+0x30/0x40 [ 42.718074] [] release_sock+0x3be/0x510 [ 42.723669] [] tcp_sendpage+0xaff/0x1830 [ 42.729350] [] ? sk_stream_alloc_skb+0x5d0/0x5d0 [ 42.735741] [] ? inet_sendpage+0x203/0x500 [ 42.741605] [] ? sk_stream_alloc_skb+0x5d0/0x5d0 [ 42.747990] [] inet_sendpage+0x2d7/0x500 [ 42.753668] [] ? inet_sendpage+0x7b/0x500 [ 42.759439] [] ? inet_sendmsg+0x4c0/0x4c0 [ 42.765208] [] kernel_sendpage+0x8d/0xe0 [ 42.770888] [] sock_sendpage+0x8c/0xc0 [ 42.776396] [] ? page_cache_pipe_buf_release+0x70/0x70 [ 42.783292] [] ? kernel_sendpage+0xe0/0xe0 [ 42.789146] [] pipe_to_sendpage+0x264/0x320 [ 42.795092] [] ? direct_splice_actor+0x180/0x180 [ 42.801467] [] ? splice_from_pipe_next+0x2a4/0x380 [ 42.808015] [] __splice_from_pipe+0x2ff/0x6f0 [ 42.814133] [] ? direct_splice_actor+0x180/0x180 [ 42.820509] [] splice_from_pipe+0xf9/0x160 [ 42.826365] [] ? direct_splice_actor+0x180/0x180 [ 42.832747] [] ? splice_shrink_spd+0x60/0x60 [ 42.838775] [] generic_splice_sendpage+0x40/0x50 [ 42.845149] [] ? splice_from_pipe+0x160/0x160 [ 42.851262] [] direct_splice_actor+0x125/0x180 [ 42.857464] [] splice_direct_to_actor+0x2d2/0x830 [ 42.863926] [] ? generic_pipe_buf_nosteal+0x10/0x10 [ 42.870562] [] ? do_splice_to+0x140/0x140 [ 42.876353] [] ? security_file_permission+0x89/0x1e0 [ 42.883096] [] ? rw_verify_area+0x100/0x2f0 [ 42.889042] [] do_splice_direct+0x1a7/0x270 [ 42.894988] [] ? splice_direct_to_actor+0x830/0x830 [ 42.901627] [] ? rw_verify_area+0x100/0x2f0 [ 42.907578] [] do_sendfile+0x54c/0xd30 [ 42.913106] [] ? __compat_sys_pwritev64+0xf0/0xf0 [ 42.919583] [] ? __might_fault+0xe4/0x1d0 [ 42.925364] [] ? __might_fault+0x114/0x1d0 [ 42.931225] [] SyS_sendfile64+0xc3/0x150 [ 42.936903] [] ? SyS_sendfile+0x160/0x160 [ 42.942679] [] ? lockdep_sys_exit_thunk+0x12/0x14 [ 42.949495] [] entry_SYSCALL_64_fastpath+0x1c/0x98 [ 42.956554] Dumping ftrace buffer: [ 42.960182] (ftrace buffer empty) [ 42.963867] Kernel Offset: disabled [ 42.967525] Rebooting in 86400 seconds..