[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 14.767500] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 19.402477] random: sshd: uninitialized urandom read (32 bytes read) [ 19.620331] random: sshd: uninitialized urandom read (32 bytes read) [ 20.131704] random: sshd: uninitialized urandom read (32 bytes read) [ 34.862737] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.15.192' (ECDSA) to the list of known hosts. [ 40.515210] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 40.713868] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 40.722200] IP: [] l2tp_session_free+0x11c/0x200 [ 40.728625] PGD 1c41e7067 [ 40.731271] PUD 1c8e2d067 PMD 0 [ 40.734754] [ 40.736388] Oops: 0002 [#1] PREEMPT SMP KASAN [ 40.740860] Dumping ftrace buffer: [ 40.744413] (ftrace buffer empty) [ 40.748109] Modules linked in: [ 40.751403] CPU: 0 PID: 3673 Comm: syz-executor047 Not tainted 4.9.122-g54068d6 #26 [ 40.759179] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.768667] task: ffff8801c3eee000 task.stack: ffff8801c32b8000 [ 40.774831] RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 [ 40.783813] RSP: 0018:ffff8801c32bfca0 EFLAGS: 00010246 [ 40.789257] RAX: dffffc0000000000 RBX: ffff8801ca98db80 RCX: 0000000000000000 [ 40.796516] RDX: 1ffff10039294e60 RSI: ffffffff836c39a1 RDI: ffff8801c94a7300 [ 40.803777] RBP: ffff8801c32bfcc0 R08: ffff8801c3eee8e8 R09: 0000000000000000 [ 40.811028] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801c94a7180 [ 40.818292] R13: ffff8801ca98db88 R14: 0000000000000000 R15: ffffffff83019be0 [ 40.825539] FS: 000000000171b880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 40.833754] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 40.839614] CR2: 0000000000000080 CR3: 00000001c9484000 CR4: 00000000001606f0 [ 40.846863] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 40.854193] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 40.861452] Stack: [ 40.863578] ffff8801c2d0bb80 ffff8801ca98db80 ffff8801c2d0bf50 ffff8801c2d0be58 [ 40.871567] ffff8801c32bfce8 ffffffff836cb2b2 ffff8801c2d0bfc0 ffff8801c2d0bb80 [ 40.879570] ffffffff836cb1e0 ffff8801c32bfd20 ffffffff830270f5 ffff8801c2d0bfc0 [ 40.887562] Call Trace: [ 40.890157] [] pppol2tp_session_destruct+0xd2/0x110 [ 40.896940] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 40.903287] [] __sk_destruct+0x55/0x590 [ 40.908889] [] ? sock_release+0x1c0/0x1c0 [ 40.914662] [] sk_destruct+0x63/0x80 [ 40.919997] [] __sk_free+0x4f/0x220 [ 40.925253] [] sk_free+0x2b/0x40 [ 40.930247] [] pppol2tp_release+0x239/0x2e0 [ 40.936228] [] sock_release+0x96/0x1c0 [ 40.941741] [] sock_close+0x16/0x20 [ 40.947041] [] __fput+0x263/0x700 [ 40.952129] [] ____fput+0x15/0x20 [ 40.957217] [] task_work_run+0x10c/0x180 [ 40.962911] [] exit_to_usermode_loop+0xfc/0x120 [ 40.969208] [] do_syscall_64+0x364/0x490 [ 40.974898] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 40.982002] 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 [ 41.008913] RIP [] l2tp_session_free+0x11c/0x200 [ 41.015435] RSP [ 41.019111] CR2: 0000000000000080 [ 41.022876] ---[ end trace 7f085371dd33ea7f ]--- [ 41.027637] Kernel panic - not syncing: Fatal exception [ 41.033334] Dumping ftrace buffer: [ 41.036852] (ftrace buffer empty) [ 41.040536] Kernel Offset: disabled [ 41.044136] Rebooting in 86400 seconds..