[....] 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[ 13.891494] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 14.943563] random: sshd: uninitialized urandom read (32 bytes read) [ 15.235996] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 15.754471] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.51' (ECDSA) to the list of known hosts. [ 21.432519] urandom_read: 1 callbacks suppressed [ 21.432523] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 21.633598] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 21.641847] IP: [] l2tp_session_free+0x11c/0x200 [ 21.648269] PGD 1c5e3e067 [ 21.650917] PUD 1c5c68067 PMD 0 [ 21.654398] [ 21.656022] Oops: 0002 [#1] PREEMPT SMP KASAN [ 21.660493] Dumping ftrace buffer: [ 21.664008] (ftrace buffer empty) [ 21.667695] Modules linked in: [ 21.670984] CPU: 0 PID: 3795 Comm: syz-executor811 Not tainted 4.9.122-g54068d6 #26 [ 21.678754] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 21.688087] task: ffff8801b7e56000 task.stack: ffff8801b60c8000 [ 21.694116] RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 [ 21.702970] RSP: 0018:ffff8801b60cfca0 EFLAGS: 00010246 [ 21.708393] RAX: dffffc0000000000 RBX: ffff8801ca0f8500 RCX: 0000000000000000 [ 21.715636] RDX: 1ffff10036cfc4d0 RSI: ffffffff836c39a1 RDI: ffff8801b67e2680 [ 21.722898] RBP: ffff8801b60cfcc0 R08: ffff8801b7e568e8 R09: 0000000000000000 [ 21.730145] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801b67e2500 [ 21.737390] R13: ffff8801ca0f8508 R14: 0000000000000000 R15: ffffffff83019be0 [ 21.744636] FS: 00000000022ad880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 21.753063] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 21.758925] CR2: 0000000000000080 CR3: 00000001b7ac6000 CR4: 00000000001606f0 [ 21.766172] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 21.773415] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 21.780662] Stack: [ 21.782798] ffff8801b661ee80 ffff8801ca0f8500 ffff8801b661f250 ffff8801b661f158 [ 21.790817] ffff8801b60cfce8 ffffffff836cb2b2 ffff8801b661f2c0 ffff8801b661ee80 [ 21.798855] ffffffff836cb1e0 ffff8801b60cfd20 ffffffff830270f5 ffff8801b661f2c0 [ 21.806853] Call Trace: [ 21.809421] [] pppol2tp_session_destruct+0xd2/0x110 [ 21.816067] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 21.822360] [] __sk_destruct+0x55/0x590 [ 21.827961] [] ? sock_release+0x1c0/0x1c0 [ 21.833737] [] sk_destruct+0x63/0x80 [ 21.839077] [] __sk_free+0x4f/0x220 [ 21.844328] [] sk_free+0x2b/0x40 [ 21.849323] [] pppol2tp_release+0x239/0x2e0 [ 21.855269] [] sock_release+0x96/0x1c0 [ 21.860783] [] sock_close+0x16/0x20 [ 21.866057] [] __fput+0x263/0x700 [ 21.871154] [] ____fput+0x15/0x20 [ 21.876236] [] task_work_run+0x10c/0x180 [ 21.881924] [] exit_to_usermode_loop+0xfc/0x120 [ 21.888218] [] do_syscall_64+0x364/0x490 [ 21.893908] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 21.900803] 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 95 d3 c9 fd 4c 89 ea 48 b8 00 [ 21.927904] RIP [] l2tp_session_free+0x11c/0x200 [ 21.934413] RSP [ 21.938029] CR2: 0000000000000080 [ 21.941789] ---[ end trace 396d32da0c255a3a ]--- [ 21.946554] Kernel panic - not syncing: Fatal exception [ 21.952296] Dumping ftrace buffer: [ 21.955845] (ftrace buffer empty) [ 21.959619] Kernel Offset: disabled [ 21.963221] Rebooting in 86400 seconds..