[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 13.818063] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 17.663411] random: sshd: uninitialized urandom read (32 bytes read) [ 18.055858] random: sshd: uninitialized urandom read (32 bytes read) [ 18.557410] random: sshd: uninitialized urandom read (32 bytes read) [ 35.173695] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.48' (ECDSA) to the list of known hosts. [ 40.649395] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 40.878296] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 40.886508] IP: [] l2tp_session_free+0x11c/0x200 [ 40.892938] PGD 1cc606067 [ 40.895578] PUD 1cb0cc067 PMD 0 [ 40.899073] [ 40.900696] Oops: 0002 [#1] PREEMPT SMP KASAN [ 40.905165] Dumping ftrace buffer: [ 40.908676] (ftrace buffer empty) [ 40.912357] Modules linked in: [ 40.915646] CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.9.122-g54068d6 #26 [ 40.922886] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.932225] Workqueue: sock_diag_events sock_diag_broadcast_destroy_work [ 40.939157] task: ffff8801d9bcc800 task.stack: ffff8801d9408000 [ 40.945184] RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 [ 40.954026] RSP: 0018:ffff8801d940fb00 EFLAGS: 00010246 [ 40.959451] RAX: dffffc0000000000 RBX: ffff8801b64b1680 RCX: 0000000000000000 [ 40.966697] RDX: 1ffff10036c960d0 RSI: ffffffff836c39a1 RDI: ffff8801b64b0680 [ 40.973942] RBP: ffff8801d940fb20 R08: ffff8801d9bcd110 R09: 0000000000000000 [ 40.981187] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801b64b0500 [ 40.988548] R13: ffff8801b64b1688 R14: 0000000000000000 R15: ffff8801b64b0558 [ 40.995898] FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 41.004098] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 41.010295] CR2: 0000000000000080 CR3: 00000001c9277000 CR4: 00000000001606f0 [ 41.017543] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 41.024787] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 41.032031] Stack: [ 41.034152] ffff8801b64b1728 dffffc0000000000 ffff8801b64b1680 ffffffff836cd810 [ 41.042322] ffff8801d940fb78 ffffffff836c4254 ffff8801b64b05d8 ffffed0036c960ab [ 41.050309] ffff8801b64b0558 ffff8801b64b0520 ffff8801b64b0500 ffff8801b6e00680 [ 41.058289] Call Trace: [ 41.060857] [] ? pppol2tp_connect+0x18f0/0x18f0 [ 41.067158] [] l2tp_tunnel_closeall+0x284/0x350 [ 41.073451] [] l2tp_tunnel_destruct+0x2f2/0x590 [ 41.079742] [] ? l2tp_tunnel_destruct+0x1aa/0x590 [ 41.086206] [] ? l2tp_tunnel_del_work+0x470/0x470 [ 41.092676] [] __sk_destruct+0x55/0x590 [ 41.098284] [] sk_destruct+0x63/0x80 [ 41.103631] [] sock_diag_broadcast_destroy_work+0x21a/0x390 [ 41.110968] [] process_one_work+0x7e1/0x1500 [ 41.116999] [] ? process_one_work+0x728/0x1500 [ 41.123203] [] ? pwq_dec_nr_in_flight+0x2e0/0x2e0 [ 41.129681] [] worker_thread+0xd6/0x10a0 [ 41.135370] [] ? __schedule+0x655/0x1bd0 [ 41.141056] [] kthread+0x26d/0x300 [ 41.146220] [] ? process_one_work+0x1500/0x1500 [ 41.152589] [] ? kthread_park+0xa0/0xa0 [ 41.158203] [] ? __switch_to_asm+0x34/0x70 [ 41.164062] [] ? kthread_park+0xa0/0xa0 [ 41.169668] [] ? kthread_park+0xa0/0xa0 [ 41.175269] [] ret_from_fork+0x5c/0x70 [ 41.180782] 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 [ 41.207582] RIP [] l2tp_session_free+0x11c/0x200 [ 41.214086] RSP [ 41.217683] CR2: 0000000000000080 [ 41.221113] ---[ end trace 6cc0923433164fc6 ]--- [ 41.225847] Kernel panic - not syncing: Fatal exception [ 41.231475] Dumping ftrace buffer: [ 41.234988] (ftrace buffer empty) [ 41.238671] Kernel Offset: disabled [ 41.242273] Rebooting in 86400 seconds..