[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.227353] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.547873] random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy available) [ 26.951805] random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy available) [ 27.594564] random: sshd: uninitialized urandom read (32 bytes read, 63 bits of entropy available) [ 27.822465] random: sshd: uninitialized urandom read (32 bytes read, 67 bits of entropy available) Warning: Permanently added '10.128.0.55' (ECDSA) to the list of known hosts. [ 33.541667] random: sshd: uninitialized urandom read (32 bytes read, 72 bits of entropy available) executing program [ 33.633789] BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor588/3849 [ 33.642775] caller is __this_cpu_preempt_check+0x1c/0x20 [ 33.648231] CPU: 1 PID: 3849 Comm: syz-executor588 Not tainted 4.4.151-g37af2ff #85 [ 33.656001] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.665329] 0000000000000000 ef99c674faff9369 ffff8801d9107808 ffffffff81e15eed [ 33.673321] 0000000000000001 ffffffff83c154c0 ffffffff83f0d4c0 ffff8801d96f8000 [ 33.681300] 0000000000000003 ffff8801d9107848 ffffffff81ebf7c3 ffff8801ce8e86bc [ 33.689277] Call Trace: [ 33.691845] [] dump_stack+0xc1/0x124 [ 33.697190] [] check_preemption_disabled.cold.0+0x7f/0x8b [ 33.704352] [] __this_cpu_preempt_check+0x1c/0x20 [ 33.710819] [] tcp_try_coalesce+0x22a/0x4c0 [ 33.716838] [] ? tcp_parse_options+0x970/0x970 [ 33.723054] [] tcp_queue_rcv+0x127/0x6f0 [ 33.728737] [] tcp_send_rcvq+0x3a6/0x470 [ 33.734430] [] ? tcp_rcv_established+0x1fe0/0x1fe0 [ 33.740993] [] ? do_softirq.part.16+0x60/0x60 [ 33.747117] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 33.753977] [] ? lock_sock_nested+0x90/0x120 [ 33.760018] [] ? trace_hardirqs_on+0xd/0x10 [ 33.766000] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 33.772302] [] tcp_sendmsg+0x23ec/0x2b10 [ 33.777987] [] ? debug_check_no_locks_freed+0x210/0x210 [ 33.784976] [] ? sock_has_perm+0x29f/0x400 [ 33.790843] [] ? tcp_sendpage+0x17c0/0x17c0 [ 33.796791] [] ? inet_sendmsg+0x143/0x4d0 [ 33.802565] [] inet_sendmsg+0x203/0x4d0 [ 33.808188] [] ? inet_sendmsg+0x73/0x4d0 [ 33.813878] [] ? inet_recvmsg+0x4c0/0x4c0 [ 33.819653] [] sock_sendmsg+0xcc/0x110 [ 33.825182] [] SYSC_sendto+0x21c/0x370 [ 33.830698] [] ? SYSC_connect+0x300/0x300 [ 33.836468] [] ? release_sock+0x3b6/0x500 [ 33.842244] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 33.848604] [] ? inet_stream_connect+0x78/0xa0 [ 33.854820] [] ? SYSC_connect+0x22a/0x300 [ 33.860597] [] ? sock_common_setsockopt+0x9a/0xe0 [ 33.867064] [] ? SyS_setsockopt+0x185/0x260 [ 33.873008] [] ? SyS_recv+0x40/0x40 [ 33.878259] [] ? retint_user+0x18/0x3c [ 33.883771]