[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.307756] random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.148469] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 23.502016] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 24.113546] random: sshd: uninitialized urandom read (32 bytes read, 60 bits of entropy available) [ 24.290201] random: sshd: uninitialized urandom read (32 bytes read, 63 bits of entropy available) Warning: Permanently added '10.128.10.17' (ECDSA) to the list of known hosts. [ 29.991792] random: sshd: uninitialized urandom read (32 bytes read, 67 bits of entropy available) executing program [ 30.082995] BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor070/3843 [ 30.092063] caller is __this_cpu_preempt_check+0x1c/0x20 [ 30.097499] CPU: 1 PID: 3843 Comm: syz-executor070 Not tainted 4.4.147-ga5fc665 #80 [ 30.105273] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.114604] 0000000000000000 81d6733e5ffab703 ffff8801d90e7808 ffffffff81e12a4d [ 30.122624] 0000000000000001 ffffffff83c153c0 ffffffff83f0d300 ffff8801d3920000 [ 30.130621] 0000000000000003 ffff8801d90e7848 ffffffff81ebc2f3 ffff8800b1ff2e3c [ 30.138633] Call Trace: [ 30.141199] [] dump_stack+0xc1/0x124 [ 30.146544] [] check_preemption_disabled.cold.0+0x7f/0x8b [ 30.153709] [] __this_cpu_preempt_check+0x1c/0x20 [ 30.160180] [] tcp_try_coalesce+0x22a/0x4c0 [ 30.166133] [] ? tcp_parse_options+0x970/0x970 [ 30.172349] [] tcp_queue_rcv+0x127/0x6f0 [ 30.178054] [] tcp_send_rcvq+0x3a6/0x470 [ 30.183742] [] ? tcp_rcv_established+0x1fe0/0x1fe0 [ 30.190300] [] ? __local_bh_enable_ip+0x40/0xd0 [ 30.196600] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 30.203428] [] ? lock_sock_nested+0x90/0x120 [ 30.209470] [] ? trace_hardirqs_on+0xd/0x10 [ 30.215421] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 30.221718] [] tcp_sendmsg+0x23ec/0x2b10 [ 30.227407] [] ? debug_check_no_locks_freed+0x210/0x210 [ 30.234401] [] ? sock_has_perm+0x29f/0x400 [ 30.240268] [] ? tcp_sendpage+0x17c0/0x17c0 [ 30.246234] [] ? inet_sendmsg+0x143/0x4d0 [ 30.252012] [] inet_sendmsg+0x203/0x4d0 [ 30.257617] [] ? inet_sendmsg+0x73/0x4d0 [ 30.263309] [] ? inet_recvmsg+0x4c0/0x4c0 [ 30.269084] [] sock_sendmsg+0xcc/0x110 [ 30.274600] [] SYSC_sendto+0x21c/0x370 [ 30.280115] [] ? SYSC