[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.518181] random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.455964] random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy available) [ 25.903293] random: sshd: uninitialized urandom read (32 bytes read, 40 bits of entropy available) [ 26.910111] random: sshd: uninitialized urandom read (32 bytes read, 119 bits of entropy available) [ 27.082921] random: sshd: uninitialized urandom read (32 bytes read, 123 bits of entropy available) [ 31.420991] random: nonblocking pool is initialized Warning: Permanently added '10.128.0.58' (ECDSA) to the list of known hosts. executing program [ 32.628899] BUG: using __this_cpu_add() in preemptible [00000000] code: syzkaller533266/3802 [ 32.637525] caller is __this_cpu_preempt_check+0x1c/0x20 [ 32.642978] CPU: 1 PID: 3802 Comm: syzkaller533266 Not tainted 4.4.119-g855ea74 #27 [ 32.650738] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.660062] 0000000000000000 771934c25453dbb9 ffff8801d92af638 ffffffff81d0402d [ 32.668027] 0000000000000001 ffffffff839fe5a0 ffffffff83cefc20 ffff8801c5908000 [ 32.675993] 0000000000000003 ffff8801d92af678 ffffffff81d63f84 ffff8801d0d9c5c8 [ 32.683956] Call Trace: [ 32.686516] [] dump_stack+0xc1/0x124 [ 32.691856] [] check_preemption_disabled+0x1d4/0x200 [ 32.698578] [] __this_cpu_preempt_check+0x1c/0x20 [ 32.705046] [] tcp_try_coalesce+0x249/0x4d0 [ 32.710993] [] ? __sk_mem_schedule+0x191/0xd20 [ 32.717200] [] ? tcp_parse_options+0x970/0x970 [ 32.723405] [] ? skb_copy_datagram_from_iter+0x38c/0x5a0 [ 32.730473] [] tcp_queue_rcv+0x127/0x720 [ 32.736152] [] tcp_send_rcvq+0x39b/0x450 [ 32.741836] [] ? tcp_rcv_established+0x2230/0x2230 [ 32.748387] [] ? __local_bh_enable_ip+0x30/0xd0 [ 32.754675] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 32.761485] [] ? lock_sock_nested+0x90/0x120 [ 32.767525] [] ? trace_hardirqs_on+0xd/0x10 [ 32.773466] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 32.779762] [] tcp_sendmsg+0x1e8f/0x2b10 [ 32.785443] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 32.792425] [] ? sock_has_perm+0x1c1/0x400 [ 32.798278] [] ? tcp_sendpage+0x1830/0x1830 [ 32.804217] [] ? inet_sendmsg+0x201/0x4c0 [ 32.809984] [] inet_sendmsg+0x2bc/0x4c0 [ 32.815578] [] ? inet_sendmsg+0x73/0x4c0 [ 32.821258] [] ? inet_recvmsg+0x4c0/0x4c0 [ 32.827032] [] sock_sendmsg+0xca/0x110 [ 32.832541] [] sock_write_iter+0x226/0x3b0 [ 32.838399] [] ? sock_sendmsg+0x110/0x110 [ 32.844182] [] ? rw_copy_check_uvector+0x21e/0x2b0 [ 32.850739] [] do_iter_readv_writev+0x138/0x1e0 [ 32.857026] [] ? sock_sendmsg+0x110/0x110 [ 32.862793] [] ? vfs_iter_read+0x270/0x270 [ 32.868644] [] ? rw_verify_area+0x100/0x2f0 [ 32.874585] [] ? sock_sendmsg+0x110/0x110 [ 32.880354] [] do_readv_writev+0x2d2/0x6e0 [ 32.886212] [] ? vfs_write+0x530/0x530 [ 32.891716] [] ? _raw_spin_unlock+0x2c/0x50 [ 32.897658] [] ? do_huge_pmd_anonymous_page+0x3dd/0xa10 [ 32.904639] [] ? handle_mm_fault+0x3f2/0x3190 [ 32.910757] [] vfs_writev+0x7b/0xb0 [ 32.916003] [] SyS_writev+0xd9/0x240 [ 32.921335] [] ? SyS_readv+0x240/0x240 [ 32.926840] [] ? trac