[....] Starting OpenBSD Secure Shell server: sshd[ 22.347853] random: sshd: uninitialized urandom read (32 bytes read, 36 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.210372] random: sshd: uninitialized urandom read (32 bytes read, 40 bits of entropy available) [ 26.691447] random: sshd: uninitialized urandom read (32 bytes read, 42 bits of entropy available) [ 27.728524] random: sshd: uninitialized urandom read (32 bytes read, 124 bits of entropy available) [ 27.903950] random: sshd: uninitialized urandom read (32 bytes read, 128 bits of entropy available) [ 27.962065] random: nonblocking pool is initialized Warning: Permanently added '10.128.0.48' (ECDSA) to the list of known hosts. executing program [ 33.423588] BUG: using __this_cpu_add() in preemptible [00000000] code: syzkaller457268/3794 [ 33.432222] caller is __this_cpu_preempt_check+0x1c/0x20 [ 33.437651] CPU: 0 PID: 3794 Comm: syzkaller457268 Not tainted 4.4.120-gd63fdf6 #28 [ 33.445410] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.454734] 0000000000000000 718e36e8dca64279 ffff8801d959f800 ffffffff81d0408d [ 33.462704] 0000000000000000 ffffffff839fe5a0 ffffffff83cefc20 ffff8801d96ec800 [ 33.470673] 0000000000000003 ffff8801d959f840 ffffffff81d63fe4 ffffffff810002b8 [ 33.478657] Call Trace: [ 33.481216] [] dump_stack+0xc1/0x124 [ 33.486548] [] check_preemption_disabled+0x1d4/0x200 [ 33.493267] [] ? 0xffffffff810002b8 [ 33.498510] [] __this_cpu_preempt_check+0x1c/0x20 [ 33.504974] [] tcp_try_coalesce+0x249/0x4d0 [ 33.510911] [] ? tcp_parse_options+0x970/0x970 [ 33.517112] [] ? skb_copy_datagram_from_iter+0x38c/0x5a0 [ 33.524176] [] tcp_queue_rcv+0x127/0x720 [ 33.529855] [] tcp_send_rcvq+0x39b/0x450 [ 33.535531] [] ? tcp_rcv_established+0x2230/0x2230 [ 33.542080] [] ? __local_bh_enable_ip+0x30/0xd0 [ 33.548368] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 33.555176] [] ? lock_sock_nested+0x90/0x120 [ 33.561200] [] ? trace_hardirqs_on+0xd/0x10 [ 33.567140] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 33.573430] [] tcp_sendmsg+0x1e8f/0x2b10 [ 33.579107] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 33.586089] [] ? sock_has_perm+0x1c1/0x400 [ 33.591942] [] ? tcp_sendpage+0x1830/0x1830 [ 33.597884] [] ? inet_sendmsg+0x201/0x4c0 [ 33.603648] [] inet_sendmsg+0x2bc/0x4c0 [ 33.609239] [] ? inet_sendmsg+0x73/0x4c0 [ 33.614916] [] ? inet_recvmsg+0x4c0/0x4c0 [ 33.620679] [] sock_sendmsg+0xca/0x110 [ 33.626182] [] SYSC_sendto+0x2c8/0x340 [ 33.631687] [] ? SYSC_connect+0x310/0x310 [ 33.637453] [] ? _raw_spin_unlock+0x2c/0x50 [ 33.643394] [] ? do_huge_pmd_anonymous_page+0x3dd/0xa10 [ 33.650374] [] ? handle_mm_fault+0x3f2/0x3190 [ 33.656489] [] ? __do_page_fault+0x380/0xa00 [ 33.662514] [] ? retint_user+0x18/0x3c [ 33.668030] [] SyS_sendto+0x40/0x50 [ 33.673272] [<