[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.966004] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. [ 22.014421] random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.280653] random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available) [ 23.430186] random: sshd: uninitialized urandom read (32 bytes read, 126 bits of entropy available) [ 23.567736] random: nonblocking pool is initialized Warning: Permanently added '10.128.10.5' (ECDSA) to the list of known hosts. executing program [ 29.075026] BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor886/3837 [ 29.083631] caller is __this_cpu_preempt_check+0x1c/0x20 [ 29.089064] CPU: 1 PID: 3837 Comm: syz-executor886 Not tainted 4.4.131-gaa3863d #41 [ 29.096828] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.106618] 0000000000000000 3073024b80fba18e ffff8800bb0ff5f0 ffffffff81e0df8d [ 29.114639] 0000000000000001 ffffffff83c133c0 ffffffff83f0a640 ffff8800bb33c800 [ 29.122608] 0000000000000003 ffff8800bb0ff630 ffffffff81eb7893 ffff8800b0ce16bc [ 29.130582] Call Trace: [ 29.133143] [] dump_stack+0xc1/0x124 [ 29.138483] [] check_preemption_disabled.cold.0+0x7f/0x8b [ 29.145639] [] __this_cpu_preempt_check+0x1c/0x20 [ 29.152101] [] tcp_try_coalesce+0x22a/0x4c0 [ 29.158080] [] ? tcp_parse_options+0x970/0x970 [ 29.164282] [] tcp_queue_rcv+0x127/0x6f0 [ 29.169966] [] tcp_send_rcvq+0x3a6/0x470 [ 29.175644] [] ? tcp_rcv_established+0x1fe0/0x1fe0 [ 29.182191] [] ? trace_event_raw_event_irq_handler_exit+0x1b0/0x1e0 [ 29.190214] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 29.197026] [] ? lock_sock_nested+0x90/0x120 [ 29.203057] [] ? trace_hardirqs_on+0xd/0x10 [ 29.209004] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 29.215999] [] tcp_sendmsg+0x231e/0x2b20 [ 29.221683] [] ? sock_has_perm+0x29f/0x400 [ 29.227541] [] ? tcp_sendpage+0x1840/0x1840 [ 29.233487] [] ? inet_sendmsg+0x143/0x4d0 [ 29.239254] [] inet_sendmsg+0x203/0x4d0 [ 29.244845] [] ? inet_sendmsg+0x73/0x4d0 [ 29.250523] [] ? inet_recvmsg+0x4c0/0x4c0 [ 29.256289] [] sock_sendmsg+0xcc/0x110 [ 29.261795] [] ___sys_sendmsg+0x441/0x880 [ 29.267564] [] ? debug_check_no_locks_freed+0x210/0x210 [ 29.274549] [] ? copy_msghdr_from_user+0x550/0x550 [ 29.281102] [] ? inet_recvmsg+0x4c0/0x4c0 [ 29.286870] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 29.293605] [] ? __fget_light+0x9f/0x1f0 [ 29.299285] [] ? __fdget+0x18/0x20 [ 29.305138] [] __sys_sendmmsg+0x12e/0x2e0 [ 29.310903] [] ? SyS_sendmsg+0x50/0x50 [ 29.316414] [] ? selinux_netlbl_socket_setsockopt+0x97/0x340 [ 29.323832] [