[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 15.030345] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 15.498504] random: sshd: uninitialized urandom read (32 bytes read) [ 15.811097] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 16.765104] random: sshd: uninitialized urandom read (32 bytes read) [ 16.902005] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.56' (ECDSA) to the list of known hosts. [ 22.367378] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 22.570957] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 22.579229] IP: [] l2tp_session_free+0x11c/0x200 [ 22.585652] PGD 1c633e067 [ 22.588312] PUD 1c631c067 PMD 0 [ 22.591828] [ 22.593463] Oops: 0002 [#1] PREEMPT SMP KASAN [ 22.598031] Dumping ftrace buffer: [ 22.601560] (ftrace buffer empty) [ 22.605251] Modules linked in: [ 22.608546] CPU: 1 PID: 3794 Comm: syz-executor079 Not tainted 4.9.113-g47bbcd6 #62 [ 22.616406] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 22.625749] task: ffff8801b7e74800 task.stack: ffff8801d9bb0000 [ 22.631795] RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 [ 22.640677] RSP: 0018:ffff8801d9bb7ca0 EFLAGS: 00010246 [ 22.646113] RAX: dffffc0000000000 RBX: ffff8801b60a4500 RCX: 0000000000000000 [ 22.653362] RDX: 1ffff10039613f50 RSI: ffffffff836bcce1 RDI: ffff8801cb09fa80 [ 22.660622] RBP: ffff8801d9bb7cc0 R08: ffff8801b7e750e8 R09: 0000000000000000 [ 22.667882] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801cb09f900 [ 22.675130] R13: ffff8801b60a4508 R14: 0000000000000000 R15: ffffffff83013be0 [ 22.682381] FS: 000000000127c880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 22.690594] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 22.696459] CR2: 0000000000000080 CR3: 00000001c5540000 CR4: 00000000001606f0 [ 22.703709] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 22.711141] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 22.718394] Stack: [ 22.720519] ffff8801ca1fc400 ffff8801b60a4500 ffff8801ca1fc7d0 ffff8801ca1fc6d8 [ 22.728533] ffff8801d9bb7ce8 ffffffff836c45f2 ffff8801ca1fc840 ffff8801ca1fc400 [ 22.736553] ffffffff836c4520 ffff8801d9bb7d20 ffffffff83021095 ffff8801ca1fc840 [ 22.744559] Call Trace: [ 22.747142] [] pppol2tp_session_destruct+0xd2/0x110 [ 22.753794] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 22.760114] [] __sk_destruct+0x55/0x590 [ 22.765722] [] ? sock_release+0x1c0/0x1c0 [ 22.771497] [] sk_destruct+0x63/0x80 [ 22.776852] [] __sk_free+0x4f/0x220 [ 22.782106] [] sk_free+0x2b/0x40 [ 22.787106] [] pppol2tp_release+0x239/0x2e0 [ 22.793078] [] sock_release+0x96/0x1c0 [ 22.798610] [] sock_close+0x16/0x20 [ 22.803961] [] __fput+0x263/0x700 [ 22.809050] [] ____fput+0x15/0x20 [ 22.814146] [] task_work_run+0x10c/0x180 [ 22.819849] [] exit_to_usermode_loop+0xfc/0x120 [ 22.826245] [] do_syscall_64+0x364/0x490 [ 22.831939] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 22.838854] 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 55 1d ca fd 4c 89 ea 48 b8 00 [ 22.865760] RIP [] l2tp_session_free+0x11c/0x200 [ 22.872280] RSP [ 22.875888] CR2: 0000000000000080 [ 22.879848] ---[ end trace b448575534ca29f0 ]--- [ 22.884622] Kernel panic - not syncing: Fatal exception [ 22.890444] Dumping ftrace buffer: [ 22.893984] (ftrace buffer empty) [ 22.897679] Kernel Offset: disabled [ 22.901288] Rebooting in 86400 seconds..