[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.570089] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. [ 20.615736] random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.861194] random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available) [ 21.657194] random: sshd: uninitialized urandom read (32 bytes read, 100 bits of entropy available) [ 21.823768] random: sshd: uninitialized urandom read (32 bytes read, 107 bits of entropy available) Warning: Permanently added '10.128.0.48' (ECDSA) to the list of known hosts. [ 51.372103] random: sshd: uninitialized urandom read (32 bytes read, 122 bits of entropy available) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 51.853860] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 51.862134] IP: [] l2tp_session_free+0x11c/0x200 [ 51.868558] PGD 80000001cbe40067 PUD 1cbfab067 PMD 0 [ 51.874089] Oops: 0002 [#1] PREEMPT SMP KASAN [ 51.879023] Dumping ftrace buffer: [ 51.882539] (ftrace buffer empty) [ 51.886227] Modules linked in: [ 51.889517] CPU: 0 PID: 3957 Comm: syzkaller971971 Not tainted 4.4.115-gaa856bd #6 executing program executing program executing program executing program [ 51.897193] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.906525] task: ffff8801d8810000 task.stack: ffff8801d8f50000 [ 51.912555] RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 [ 51.921406] RSP: 0018:ffff8801d8f57cd8 EFLAGS: 00010246 [ 51.926828] RAX: dffffc0000000000 RBX: ffff8801cbe8c780 RCX: ffffffff8345abf1 [ 51.934075] RDX: 1ffff10039518750 RSI: 0000000000000001 RDI: ffff8801ca8c3a80 [ 51.941321] RBP: ffff8801d8f57cf8 R08: 0000000000000000 R09: 0000000000000000 executing program executing program executing program [ 51.948567] R10: 0000000000000000 R11: 1ffff1003b1eaf5c R12: ffff8801ca8c3900 [ 51.955813] R13: ffff8801cbe8c788 R14: 0000000000000000 R15: ffffffff82de7b90 [ 51.963060] FS: 00007fb1bad61700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 51.971259] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 51.977118] CR2: 0000000000000080 CR3: 00000001caa3e000 CR4: 0000000000160670 [ 51.984368] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 51.991613] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 51.998855] Stack: executing program executing program executing program executing program [ 52.000977] ffff8801d89e3b80 ffff8801cbe8c780 ffff8801d89e3f50 ffff8801d89e3e58 [ 52.008958] ffff8801d8f57d20 ffffffff83464a13 ffff8801d89e3b80 ffffffff83464940 [ 52.016947] ffff8800aba24ce0 ffff8801d8f57d48 ffffffff82dfca9a ffff8801d89e3b80 [ 52.024933] Call Trace: [ 52.027501] [] pppol2tp_session_destruct+0xd3/0x110 [ 52.034142] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 52.040448] [] sk_destruct+0x4a/0x4c0 [ 52.045874] [] __sk_free+0x57/0x230 executing program executing program executing program executing program [ 52.051126] [] sk_free+0x30/0x40 [ 52.056113] [] pppol2tp_release+0x27a/0x310 [ 52.062059] [] sock_release+0x8d/0x1e0 [ 52.067568] [] sock_close+0x16/0x20 [ 52.072820] [] __fput+0x233/0x6d0 [ 52.077915] [] ____fput+0x15/0x20 [ 52.082996] [] task_work_run+0x104/0x180 [ 52.088683] [] exit_to_usermode_loop+0x13d/0x160 [ 52.095064] [] syscall_return_slowpath+0x1b5/0x1f0 executing program executing program executing program executing program executing program executing program [ 52.101623] [] int_ret_from_sys_call+0x25/0xa3 [ 52.107828] 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 c3 00 00 00 4d 8b b4 24 80 01 00 00 41 ff 8e 80 00 00 00 74 64 e8 55 61 f0 fd e8 50 61 f0 fd 4c [ 52.134584] RIP [] l2tp_session_free+0x11c/0x200 [ 52.141088] RSP [ 52.144685] CR2: 0000000000000080 executing program [ 52.173553] ---[ end trace 18adfd4322ec3827 ]--- [ 52.202576] Kernel panic - not syncing: Fatal exception [ 52.208330] Dumping ftrace buffer: [ 52.211850] (ftrace buffer empty) [ 52.215536] Kernel Offset: disabled [ 52.219134] Rebooting in 86400 seconds..