[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 15.844083] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 19.226161] random: sshd: uninitialized urandom read (32 bytes read) [ 19.558659] random: sshd: uninitialized urandom read (32 bytes read) [ 20.074915] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.44' (ECDSA) to the list of known hosts. [ 25.611584] urandom_read: 1 callbacks suppressed [ 25.611587] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 25.815060] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 25.823296] IP: [] l2tp_session_free+0x11c/0x200 [ 25.829714] PGD 1b8d98067 [ 25.832364] PUD 1b7bbb067 PMD 0 [ 25.835837] [ 25.837465] Oops: 0002 [#1] PREEMPT SMP KASAN [ 25.841932] Dumping ftrace buffer: [ 25.845446] (ftrace buffer empty) [ 25.849134] Modules linked in: [ 25.852454] CPU: 1 PID: 3792 Comm: syz-executor280 Not tainted 4.9.117-g8b21e85 #71 [ 25.860221] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.869551] task: ffff8801b70c6000 task.stack: ffff8801d9838000 [ 25.875579] RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 [ 25.884424] RSP: 0018:ffff8801d983fca0 EFLAGS: 00010246 [ 25.889845] RAX: dffffc0000000000 RBX: ffff8801cc721b80 RCX: 0000000000000000 [ 25.897089] RDX: 1ffff100398e4300 RSI: ffffffff836bf8f1 RDI: ffff8801cc721800 [ 25.904342] RBP: ffff8801d983fcc0 R08: ffff8801b70c68e8 R09: 0000000000000000 [ 25.911585] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801cc721680 [ 25.918846] R13: ffff8801cc721b88 R14: 0000000000000000 R15: ffffffff83015be0 [ 25.926094] FS: 0000000000b01880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 25.934292] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 25.940171] CR2: 0000000000000080 CR3: 00000001c4e34000 CR4: 00000000001606f0 [ 25.947419] Stack: [ 25.949542] ffff8801d9528880 ffff8801cc721b80 ffff8801d9528c50 ffff8801d9528b58 [ 25.957535] ffff8801d983fce8 ffffffff836c7202 ffff8801d9528cc0 ffff8801d9528880 [ 25.965526] ffffffff836c7130 ffff8801d983fd20 ffffffff83023095 ffff8801d9528cc0 [ 25.973514] Call Trace: [ 25.976076] [] pppol2tp_session_destruct+0xd2/0x110 [ 25.982728] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 25.982734] [] __sk_destruct+0x55/0x590 [ 25.982739] [] ? sock_release+0x1c0/0x1c0 [ 25.982743] [] sk_destruct+0x63/0x80 [ 25.982746] [] __sk_free+0x4f/0x220 [ 25.982755] [] sk_free+0x2b/0x40 [ 25.982759] [] pppol2tp_release+0x239/0x2e0 [ 25.982763] [] sock_release+0x96/0x1c0 [ 25.982767] [] sock_close+0x16/0x20 [ 25.982773] [] __fput+0x263/0x700 [ 25.982777] [] ____fput+0x15/0x20 [ 25.982783] [] task_work_run+0x10c/0x180 [ 25.982789] [] exit_to_usermode_loop+0xfc/0x120 [ 25.982792] [] do_syscall_64+0x364/0x490 [ 25.982798] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 25.982863] Code: 49 8d bc 24 80 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 c6 00 00 00 4d 8b b4 24 80 01 00 00 41 ff 8e 80 00 00 00 74 69 e8 e5 f1 c9 fd 4c 89 ea 48 b8 00 [ 25.982868] RIP [] l2tp_session_free+0x11c/0x200 [ 25.982869] RSP [ 25.982871] CR2: 0000000000000080 [ 25.984107] ---[ end trace e47ec2162443922a ]--- [ 25.984109] Kernel panic - not syncing: Fatal exception [ 25.989322] Dumping ftrace buffer: [ 25.989324] (ftrace buffer empty) [ 25.989326] Kernel Offset: disabled [ 26.120856] Rebooting in 86400 seconds..