[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 22.075034] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.927116] random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available) [ 26.238695] random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available) [ 27.267487] random: sshd: uninitialized urandom read (32 bytes read, 99 bits of entropy available) [ 27.438690] random: sshd: uninitialized urandom read (32 bytes read, 101 bits of entropy available) Warning: Permanently added '10.128.0.43' (ECDSA) to the list of known hosts. [ 32.865944] random: sshd: uninitialized urandom read (32 bytes read, 106 bits of entropy available) 2018/05/14 12:41:21 parsed 1 programs 2018/05/14 12:41:21 executed programs: 0 [ 33.445071] IPVS: Creating netns size=2552 id=1 [ 33.713750] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.730385] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.816920] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.832933] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.923558] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.938417] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.955205] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.973101] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.796776] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 34.841205] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 35.160055] BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor0/4193 [ 35.168546] caller is __this_cpu_preempt_check+0x1c/0x20 [ 35.174096] CPU: 0 PID: 4193 Comm: syz-executor0 Not tainted 4.4.131-gaa3863d #39 [ 35.181720] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.191053] 0000000000000000 1fa660b96d1720ab ffff8801d7377570 ffffffff81e0df8d [ 35.199047] 0000000000000000 ffffffff83c133c0 ffffffff83f0a640 ffff8801d71a8000 [ 35.207061] 0000000000000003 ffff8801d73775b0 ffffffff81eb7893 ffff8801d827e43c [ 35.215069] Call Trace: [ 35.217657] [] dump_stack+0xc1/0x124 [ 35.223008] [] check_preemption_disabled.cold.0+0x7f/0x8b [ 35.230179] [] __this_cpu_preempt_check+0x1c/0x20 [ 35.236745] [] tcp_try_coalesce+0x22a/0x4c0 [ 35.242700] [] ? tcp_parse_options+0x970/0x970 [ 35.248910] [] tcp_queue_rcv+0x127/0x6f0 [ 35.254607] [] tcp_send_rcvq+0x3a6/0x470 [ 35.260295] [] ? tcp_rcv_established+0x1fe0/0x1fe0 [ 35.266867] [] ? trace_event_raw_event_irq_handler_exit+0x1b0/0x1e0 [ 35.274916] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 35.281745] [] ? lock_sock_nested+0x90/0x120 [ 35.287814] [] ? trace_hardirqs_on+0xd/0x10 [ 35.293787] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 35.300111] [] tcp_sendmsg+0x231e/0x2b20 [ 35.305816] [] ? sock_has_perm+0x29f/0x400 [ 35.311705] [] ? tcp_sendpage+0x1840/0x1840 [ 35.317660] [] ? inet_sendmsg+0x143/0x4d0 [ 35.323444] [] inet_sendmsg+0x203/0x4d0 [ 35.329046] [] ? inet_sendmsg+0x73/0x4d0 [ 35.334736] [] ? inet_recvmsg+0x4c0/0x4c0 [ 35.340617] [] sock_sendmsg+0xcc/0x110 [ 35.346154] [] ___sys_sendmsg+0x441/0x880 [ 35.351955] [] ? hash_futex+0x15/0x210 [ 35.357478] [] ? copy_msghdr_from_user+0x550/0x550 [ 35.364067] [] ? futex_wake+0x153/0x460 [ 35.369869] [] ? tcp_sendpage+0x1840/0x1840 [ 35.375844] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 35.382592] [] ? __fget_light+0x9f/0x1f0 [ 35.388291] [] ? __fdget+0x18/0x20 [ 35.393466] [] ? sockfd_lookup_light+0xb6/0x160 [ 35.399872] [] __sys_sendmmsg+0x1d4/0x2e0 [ 35.405685] [] ? SyS_sendmsg+0x50/0x50 [ 35.411220] [] ? selinux_netlbl_sock_rcv_skb+0x400/0x400 [ 35.418320] [] ? compat_SyS_futex+0x1e1/0x2f0 [ 35.424473] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 35.431493] [] ? compat_SyS_setsockopt+0x18d/0x2a0 [ 35.438069] [] ? sock_common_setsockopt+0xe0/0xe0 [ 35.444557] [] ? scm_detach_fds_compat+0x3b0/0x3b0 [ 35.451139] [] compat_SyS_sendmmsg+0x32/0x40 [ 35.457195] [] ? compat_SyS