[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 12.884927] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 17.855534] random: sshd: uninitialized urandom read (32 bytes read) [ 18.264193] random: sshd: uninitialized urandom read (32 bytes read) [ 18.753815] random: sshd: uninitialized urandom read (32 bytes read) [ 18.892217] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.15.197' (ECDSA) to the list of known hosts. [ 24.624624] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 24.823665] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 24.831971] IP: [] l2tp_session_free+0x11c/0x200 [ 24.838410] PGD 1c8b94067 [ 24.841136] PUD 1c8b8a067 PMD 0 [ 24.844647] [ 24.846272] Oops: 0002 [#1] PREEMPT SMP KASAN [ 24.850756] Dumping ftrace buffer: [ 24.854286] (ftrace buffer empty) [ 24.857975] Modules linked in: [ 24.861264] CPU: 0 PID: 3728 Comm: syz-executor149 Not tainted 4.9.122-g54068d6 #26 [ 24.869059] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 24.878393] task: ffff8801bff90000 task.stack: ffff8801cadb0000 [ 24.884577] RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 [ 24.893480] RSP: 0018:ffff8801cadb7ca0 EFLAGS: 00010246 [ 24.898972] RAX: dffffc0000000000 RBX: ffff8801c02a4780 RCX: 0000000000000000 [ 24.906270] RDX: 1ffff10037faf750 RSI: ffffffff836c39a1 RDI: ffff8801bfd7ba80 [ 24.913527] RBP: ffff8801cadb7cc0 R08: ffff8801bff908e8 R09: 0000000000000000 [ 24.920802] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801bfd7b900 [ 24.928272] R13: ffff8801c02a4788 R14: 0000000000000000 R15: ffffffff83019be0 [ 24.935524] FS: 0000000002119880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 24.943815] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 24.949697] CR2: 0000000000000080 CR3: 00000001c8837000 CR4: 00000000001606f0 [ 24.956955] Stack: [ 24.959090] ffff8801bec65500 ffff8801c02a4780 ffff8801bec658d0 ffff8801bec657d8 [ 24.967215] ffff8801cadb7ce8 ffffffff836cb2b2 ffff8801bec65940 ffff8801bec65500 [ 24.975282] ffffffff836cb1e0 ffff8801cadb7d20 ffffffff830270f5 ffff8801bec65940 [ 24.983336] Call Trace: [ 24.985916] [] pppol2tp_session_destruct+0xd2/0x110 [ 24.992563] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 24.999084] [] __sk_destruct+0x55/0x590 [ 25.004708] [] ? sock_release+0x1c0/0x1c0 [ 25.010489] [] sk_destruct+0x63/0x80 [ 25.015889] [] __sk_free+0x4f/0x220 [ 25.021172] [] sk_free+0x2b/0x40 [ 25.026184] [] pppol2tp_release+0x239/0x2e0 [ 25.032138] [] sock_release+0x96/0x1c0 [ 25.037663] [] sock_close+0x16/0x20 [ 25.042925] [] __fput+0x263/0x700 [ 25.048015] [] ____fput+0x15/0x20 [ 25.053103] [] task_work_run+0x10c/0x180 [ 25.058811] [] exit_to_usermode_loop+0xfc/0x120 [ 25.065112] [] do_syscall_64+0x364/0x490 [ 25.070863] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 25.077772] 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 [ 25.105275] RIP [] l2tp_session_free+0x11c/0x200 [ 25.111786] RSP [ 25.115389] CR2: 0000000000000080 [ 25.119138] ---[ end trace 8a2db355e1927962 ]--- [ 25.123905] Kernel panic - not syncing: Fatal exception [ 25.129554] Dumping ftrace buffer: [ 25.133075] (ftrace buffer empty) [ 25.136763] Kernel Offset: disabled [ 25.140365] Rebooting in 86400 seconds..