[....] 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[ 21.915556] 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: [ 26.277083] random: sshd: uninitialized urandom read (32 bytes read, 40 bits of entropy available) [ 26.597700] random: sshd: uninitialized urandom read (32 bytes read, 40 bits of entropy available) [ 27.521013] random: nonblocking pool is initialized Warning: Permanently added '10.128.0.3' (ECDSA) to the list of known hosts. executing program [ 33.737220] BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor240/3844 [ 33.746151] caller is __this_cpu_preempt_check+0x1c/0x20 [ 33.751573] CPU: 0 PID: 3844 Comm: syz-executor240 Not tainted 4.4.137-ga2e2217 #61 [ 33.759344] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.768672] 0000000000000000 fe213a957e3f8ed3 ffff8800bba9f808 ffffffff81e0ee0d [ 33.776643] 0000000000000000 ffffffff83c137c0 ffffffff83f0acc0 ffff8801d9246000 [ 33.784636] 0000000000000003 ffff8800bba9f848 ffffffff81eb8713 ffff8800b14e7bbc [ 33.792635] Call Trace: [ 33.795205] [] dump_stack+0xc1/0x124 [ 33.800542] [] check_preemption_disabled.cold.0+0x7f/0x8b [ 33.807702] [] __this_cpu_preempt_check+0x1c/0x20 [ 33.814176] [] tcp_try_coalesce+0x22a/0x4c0 [ 33.820119] [] ? tcp_parse_options+0x970/0x970 [ 33.826321] [] tcp_queue_rcv+0x127/0x6f0 [ 33.832002] [] tcp_send_rcvq+0x3a6/0x470 [ 33.837680] [] ? tcp_rcv_established+0x1fe0/0x1fe0 [ 33.844232] [] ? __local_bh_enable_ip+0x20/0xd0 [ 33.850522] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 33.857334] [] ? lock_sock_nested+0x90/0x120 [ 33.863374] [] ? trace_hardirqs_on+0xd/0x10 [ 33.869318] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 33.875613] [] tcp_sendmsg+0x23e6/0x2b00 [ 33.881299] [] ? debug_check_no_locks_freed+0x210/0x210 [ 33.888290] [] ? sock_has_perm+0x29f/0x400 [ 33.894153] [] ? tcp_sendpage+0x1840/0x1840 [ 33.900102] [] ? inet_sendmsg+0x143/0x4d0 [ 33.905886] [] inet_sendmsg+0x203/0x4d0 [ 33.911480] [] ? inet_sendmsg+0x73/0x4d0 [ 33.917159] [] ? inet_recvmsg+0x4c0/0x4c0 [ 33.922931] [] sock_sendmsg+0xcc/0x110 [ 33.928436] [] SYSC_sendto+0x21c/0x370 [ 33.933941] [] ? SYSC_connect+0x300/0x300 [ 33.939708] [] ? release_sock+0x3b6/0x500 [ 33.945476] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 33.951765] [] ? inet_stream_connect+0x78/0xa0 [ 33.957966] [] ? SYSC_connect+0x22a/0x300 [ 33.963735] [] ? sock_common_setsockopt+0x9a/0xe0 [ 33.970202] [] ? vfs_writev+0x83/0xb0 [ 33.975622] [] ? SyS_writev+0x174/0x250 [ 33.981224] [] ? SyS_readv+0x250/0x250 [ 33.986732] [