[....] Starting OpenBSD Secure Shell server: sshd[ 21.100625] random: sshd: uninitialized urandom read (32 bytes read, 31 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c[ 21.193463] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) . [ 21.496331] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [ 22.092998] random: sshd: uninitialized urandom read (32 bytes read, 58 bits of entropy available) [ 22.262258] random: sshd: uninitialized urandom read (32 bytes read, 61 bits of entropy available) Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.49' (ECDSA) to the list of known hosts. syzkaller login: [ 27.833412] random: sshd: uninitialized urandom read (32 bytes read, 68 bits of entropy available) executing program [ 27.931422] BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor214/3802 [ 27.940553] caller is __this_cpu_preempt_check+0x1c/0x20 [ 27.945994] CPU: 1 PID: 3802 Comm: syz-executor214 Not tainted 4.4.147-ga5fc665 #80 [ 27.953763] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 27.963091] 0000000000000000 ecab98383c18cd1f ffff8801d906f808 ffffffff81e12a4d [ 27.971131] 0000000000000001 ffffffff83c153c0 ffffffff83f0d300 ffff8800adfb1800 [ 27.979132] 0000000000000003 ffff8801d906f848 ffffffff81ebc2f3 ffff8801d0e896bc [ 27.987151] Call Trace: [ 27.989717] [] dump_stack+0xc1/0x124 [ 27.995057] [] check_preemption_disabled.cold.0+0x7f/0x8b [ 28.002231] [] __this_cpu_preempt_check+0x1c/0x20 [ 28.008702] [] tcp_try_coalesce+0x22a/0x4c0 [ 28.014656] [] ? tcp_parse_options+0x970/0x970 [ 28.020865] [] tcp_queue_rcv+0x127/0x6f0 [ 28.026565] [] tcp_send_rcvq+0x3a6/0x470 [ 28.032265] [] ? tcp_rcv_established+0x1fe0/0x1fe0 [ 28.038864] [] ? __local_bh_enable_ip+0x40/0xd0 [ 28.045158] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 28.052005] [] ? lock_sock_nested+0x90/0x120 [ 28.058047] [] ? trace_hardirqs_on+0xd/0x10 [ 28.064006] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 28.070313] [] tcp_sendmsg+0x23ec/0x2b10 [ 28.075996] [] ? debug_check_no_locks_freed+0x210/0x210 [ 28.082998] [] ? sock_has_perm+0x29f/0x400 [ 28.088858] [] ? tcp_sendpage+0x17c0/0x17c0 [ 28.094816] [] ? inet_sendmsg+0x143/0x4d0 [ 28.100587] [] inet_sendmsg+0x203/0x4d0 [ 28.106181] [] ? inet_sendmsg+0x73/0x4d0 [ 28.111864] [] ? inet_recvmsg+0x4c0/0x4c0 [ 28.117636] [] sock_sendmsg+0xcc/0x110 [ 28.123162] [] SYSC_sendto+0x21c/0x370 [ 28.128687] [] ? SYS