[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 16.183832] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 18.169210] random: sshd: uninitialized urandom read (32 bytes read) [ 18.358254] random: sshd: uninitialized urandom read (32 bytes read) [ 18.851112] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.9' (ECDSA) to the list of known hosts. [ 24.470793] urandom_read: 1 callbacks suppressed [ 24.470796] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 24.696391] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 24.704631] IP: [<ffffffff836c39cc>] l2tp_session_free+0x11c/0x200 [ 24.711076] PGD 1b8914067 [ 24.713723] PUD 1c7702067 PMD 0 [ 24.717204] [ 24.718829] Oops: 0002 [#1] PREEMPT SMP KASAN [ 24.723324] Dumping ftrace buffer: [ 24.726841] (ftrace buffer empty) [ 24.730528] Modules linked in: [ 24.733817] CPU: 1 PID: 3801 Comm: syz-executor162 Not tainted 4.9.122-g54068d6 #78 [ 24.741608] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 24.750966] task: ffff8801b7b73000 task.stack: ffff8801b79c0000 [ 24.756999] RIP: 0010:[<ffffffff836c39cc>] [<ffffffff836c39cc>] l2tp_session_free+0x11c/0x200 [ 24.766134] RSP: 0018:ffff8801b79c7ca0 EFLAGS: 00010246 [ 24.771560] RAX: dffffc0000000000 RBX: ffff8801b5eee500 RCX: 0000000000000000 [ 24.778812] RDX: 1ffff10036bdddc0 RSI: ffffffff836c39a1 RDI: ffff8801b5eeee00 [ 24.786084] RBP: ffff8801b79c7cc0 R08: ffff8801b7b738e8 R09: 0000000000000000 [ 24.793332] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801b5eeec80 [ 24.800650] R13: ffff8801b5eee508 R14: 0000000000000000 R15: ffffffff83019be0 [ 24.807920] FS: 00000000026cb880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 24.816136] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 24.821998] CR2: 0000000000000080 CR3: 00000001c3fec000 CR4: 00000000001606f0 [ 24.829249] Stack: [ 24.831375] ffff8801b5f82a80 ffff8801b5eee500 ffff8801b5f82e50 ffff8801b5f82d58 [ 24.839375] ffff8801b79c7ce8 ffffffff836cb2b2 ffff8801b5f82ec0 ffff8801b5f82a80 [ 24.847380] ffffffff836cb1e0 ffff8801b79c7d20 ffffffff830270f5 ffff8801b5f82ec0 [ 24.855523] Call Trace: [ 24.858094] [<ffffffff836cb2b2>] pppol2tp_session_destruct+0xd2/0x110 [ 24.864740] [<ffffffff836cb1e0>] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 24.871039] [<ffffffff830270f5>] __sk_destruct+0x55/0x590 [ 24.876646] [<ffffffff83019be0>] ? sock_release+0x1c0/0x1c0 [ 24.882422] [<ffffffff8302eb83>] sk_destruct+0x63/0x80 [ 24.887763] [<ffffffff8302ebef>] __sk_free+0x4f/0x220 [ 24.893055] [<ffffffff8302edeb>] sk_free+0x2b/0x40 [ 24.898056] [<ffffffff836ce5b9>] pppol2tp_release+0x239/0x2e0 [ 24.904072] [<ffffffff83019ab6>] sock_release+0x96/0x1c0 [ 24.909664] [<ffffffff83019bf6>] sock_close+0x16/0x20 [ 24.914958] [<ffffffff8157bdd3>] __fput+0x263/0x700 [ 24.920045] [<ffffffff8157c2f5>] ____fput+0x15/0x20 [ 24.925132] [<ffffffff8119a62c>] task_work_run+0x10c/0x180 [ 24.930827] [<ffffffff8100559c>] exit_to_usermode_loop+0xfc/0x120 [ 24.937126] [<ffffffff810064d4>] do_syscall_64+0x364/0x490 [ 24.942822] [<ffffffff83a00cd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 24.949727] 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 <f0> 41 ff 8e 80 00 00 00 74 69 e8 95 d3 c9 fd 4c 89 ea 48 b8 00 [ 24.976738] RIP [<ffffffff836c39cc>] l2tp_session_free+0x11c/0x200 [ 24.983251] RSP <ffff8801b79c7ca0> [ 24.986852] CR2: 0000000000000080 [ 24.990383] ---[ end trace 15112dd0f8485063 ]--- [ 24.995136] Kernel panic - not syncing: Fatal exception [ 25.000828] Dumping ftrace buffer: [ 25.004359] (ftrace buffer empty) [ 25.009345] Kernel Offset: disabled [ 25.012954] Rebooting in 86400 seconds..