[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.895519] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.905512] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 26.133835] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 27.154369] random: nonblocking pool is initialized Warning: Permanently added '10.128.0.23' (ECDSA) to the list of known hosts. executing program [ 32.970187] BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor668/3838 [ 32.978805] caller is __this_cpu_preempt_check+0x1c/0x20 [ 32.984270] CPU: 1 PID: 3838 Comm: syz-executor668 Not tainted 4.4.129-g23eaecc #27 [ 32.992072] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.001431] 0000000000000000 effbd84c17bf0852 ffff8801d956f808 ffffffff81e0dc8d [ 33.009477] 0000000000000001 ffffffff83c132c0 ffffffff83f0a4c0 ffff8801ca9a9800 [ 33.017457] 0000000000000003 ffff8801d956f848 ffffffff81eb75b3 ffff8801cbb7693c [ 33.025446] Call Trace: [ 33.028007] [] dump_stack+0xc1/0x124 [ 33.033346] [] check_preemption_disabled.cold.0+0x7f/0x8b [ 33.040504] [] __this_cpu_preempt_check+0x1c/0x20 [ 33.046971] [] tcp_try_coalesce+0x22a/0x4c0 [ 33.052916] [] ? tcp_parse_options+0x970/0x970 [ 33.059118] [] tcp_queue_rcv+0x127/0x6f0 [ 33.064801] [] tcp_send_rcvq+0x3a6/0x470 [ 33.070484] [] ? tcp_rcv_established+0x1fe0/0x1fe0 [ 33.077056] [] ? trace_event_raw_event_irq_handler_exit+0x1b0/0x1e0 [ 33.085084] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 33.091899] [] ? lock_sock_nested+0x90/0x120 [ 33.097930] [] ? trace_hardirqs_on+0xd/0x10 [ 33.103874] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 33.110167] [] tcp_sendmsg+0x231e/0x2b20 [ 33.115851] [] ? debug_check_no_locks_freed+0x210/0x210 [ 33.122849] [] ? sock_has_perm+0x29f/0x400 [ 33.128717] [] ? tcp_sendpage+0x1840/0x1840 [ 33.134688] [] ? inet_sendmsg+0x143/0x4d0 [ 33.140460] [] inet_sendmsg+0x203/0x4d0 [ 33.146058] [] ? inet_sendmsg+0x73/0x4d0 [ 33.151742] [] ? inet_recvmsg+0x4c0/0x4c0 [ 33.157524] [] sock_sendmsg+0xcc/0x110 [ 33.163062] [] SYSC_sendto+0x21c/0x370 [ 33.168572] [