[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 22.231559] random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.222547] random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy available) [ 26.547339] random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy available) [ 27.407283] random: sshd: uninitialized urandom read (32 bytes read, 98 bits of entropy available) [ 27.582049] random: sshd: uninitialized urandom read (32 bytes read, 102 bits of entropy available) Warning: Permanently added '10.128.0.18' (ECDSA) to the list of known hosts. [ 32.993120] random: sshd: uninitialized urandom read (32 bytes read, 110 bits of entropy available) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 33.832358] BUG: using __this_cpu_add() in preemptible [00000000] code: syzkaller906941/4005 [ 33.841034] caller is __this_cpu_preempt_check+0x1c/0x20 [ 33.846717] CPU: 0 PID: 4005 Comm: syzkaller906941 Not tainted 4.4.113-g962d1f3 #2 [ 33.854416] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.863757] 0000000000000000 57205c3234ad5928 ffff8800bbadf6c8 ffffffff81d028ed [ 33.871951] 0000000000000000 ffffffff839fe3a0 ffffffff83cef6a0 ffff8801d79397c0 executing program executing program executing program executing program [ 33.879983] 0000000000000003 ffff8800bbadf708 ffffffff81d62834 ffffffff810002b8 [ 33.888013] Call Trace: [ 33.890588] [] dump_stack+0xc1/0x124 [ 33.895941] [] check_preemption_disabled+0x1d4/0x200 [ 33.902683] [] ? 0xffffffff810002b8 [ 33.907955] [] __this_cpu_preempt_check+0x1c/0x20 [ 33.914443] [] tcp_try_coalesce+0x249/0x4d0 [ 33.920416] [] ? tcp_parse_options+0x970/0x970 executing program executing program executing program executing program [ 33.926646] [] ? skb_copy_datagram_from_iter+0x38c/0x5a0 [ 33.933746] [] tcp_queue_rcv+0x127/0x720 [ 33.939449] [] tcp_send_rcvq+0x39b/0x450 [ 33.945142] [] ? tcp_rcv_established+0x2230/0x2230 [ 33.951721] [] ? do_softirq.part.17+0x40/0x60 [ 33.957870] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 33.964702] [] ? lock_sock_nested+0x90/0x120 [ 33.970752] [] ? trace_hardirqs_on+0xd/0x10 [ 33.976718] [] ? __local_bh_enable_ip+0x6a/0xd0 executing program executing program executing program executing program executing program [ 33.983021] [] tcp_sendmsg+0x1e8f/0x2b10 [ 33.988726] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 33.995747] [] ? sock_has_perm+0x1c2/0x3e0 [ 34.001623] [] ? tcp_sendpage+0x1830/0x1830 [ 34.007587] [] ? inet_sendmsg+0x201/0x4c0 [ 34.013368] [] inet_sendmsg+0x2bc/0x4c0 [ 34.018976] [] ? inet_sendmsg+0x73/0x4c0 [ 34.024675] [] ? inet_recvmsg+0x4c0/0x4c0 executing program executing program executing program executing program [ 34.030467] [] sock_sendmsg+0xca/0x110 [ 34.035990] [] ___sys_sendmsg+0x6c1/0x7c0 [ 34.041791] [] ? copy_msghdr_from_user+0x550/0x550 [ 34.048353] [] ? __fget+0x232/0x3b0 [ 34.053630] [] ? __fget+0x47/0x3b0 [ 34.058806] [] ? __fget_light+0xa1/0x1e0 [ 34.064500] [] ? __fdget+0x18/0x20 [ 34.069689] [] __sys_sendmsg+0xd3/0x190 [ 34.075311] [] ? SyS_shutdown+0x1b0/0x1b0 executing program executing program executing program executing program executing program executing program [ 34.081114] [] ? __do_page_fault+0x380/0xa00 [ 34.087170] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 34.094005] [] SyS_sendmsg+0x2d/0x50 [ 34.099358] [] entry_SYSCALL_64_fastpath+0x1c/0x98 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program