[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 16.250817] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.500424] random: sshd: uninitialized urandom read (32 bytes read) [ 25.955012] random: sshd: uninitialized urandom read (32 bytes read) [ 26.492399] random: sshd: uninitialized urandom read (32 bytes read) [ 26.643464] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.22' (ECDSA) to the list of known hosts. [ 32.094942] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 32.292985] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 32.301212] IP: [] l2tp_session_free+0x11c/0x200 [ 32.307640] PGD 1cac4f067 [ 32.310301] PUD 1cc551067 PMD 0 [ 32.313809] [ 32.315436] Oops: 0002 [#1] PREEMPT SMP KASAN [ 32.319906] Dumping ftrace buffer: [ 32.323435] (ftrace buffer empty) [ 32.327120] Modules linked in: [ 32.330407] CPU: 1 PID: 3800 Comm: syz-executor464 Not tainted 4.9.119-g9dc978d #75 [ 32.338171] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.347502] task: ffff8801b876c800 task.stack: ffff8801b6690000 [ 32.353542] RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 [ 32.362410] RSP: 0018:ffff8801b6697ca0 EFLAGS: 00010246 [ 32.367830] RAX: dffffc0000000000 RBX: ffff8801b6f2c780 RCX: 0000000000000000 [ 32.375073] RDX: 1ffff100391d5610 RSI: ffffffff836bf9a1 RDI: ffff8801c8eab080 [ 32.382321] RBP: ffff8801b6697cc0 R08: ffff8801b876d0e8 R09: 0000000000000000 [ 32.389566] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801c8eaaf00 [ 32.396809] R13: ffff8801b6f2c788 R14: 0000000000000000 R15: ffffffff83015be0 [ 32.404053] FS: 00000000021b6880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 32.412271] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 32.418126] CR2: 0000000000000080 CR3: 00000001c8f9e000 CR4: 00000000001606f0 [ 32.425372] Stack: [ 32.427496] ffff8801b74fc400 ffff8801b6f2c780 ffff8801b74fc7d0 ffff8801b74fc6d8 [ 32.435512] ffff8801b6697ce8 ffffffff836c72b2 ffff8801b74fc840 ffff8801b74fc400 [ 32.443504] ffffffff836c71e0 ffff8801b6697d20 ffffffff830230f5 ffff8801b74fc840 [ 32.451502] Call Trace: [ 32.454182] [] pppol2tp_session_destruct+0xd2/0x110 [ 32.460842] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 32.467137] [] __sk_destruct+0x55/0x590 [ 32.472736] [] ? sock_release+0x1c0/0x1c0 [ 32.478512] [] sk_destruct+0x63/0x80 [ 32.483859] [] __sk_free+0x4f/0x220 [ 32.489129] [] sk_free+0x2b/0x40 [ 32.494120] [] pppol2tp_release+0x239/0x2e0 [ 32.500065] [] sock_release+0x96/0x1c0 [ 32.505577] [] sock_close+0x16/0x20 [ 32.510830] [] __fput+0x263/0x700 [ 32.515908] [] ____fput+0x15/0x20 [ 32.520993] [] task_work_run+0x10c/0x180 [ 32.526712] [] exit_to_usermode_loop+0xfc/0x120 [ 32.533016] [] do_syscall_64+0x364/0x490 [ 32.538729] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 32.545627] 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 f5 f0 c9 fd 4c 89 ea 48 b8 00 [ 32.572592] RIP [] l2tp_session_free+0x11c/0x200 [ 32.579109] RSP [ 32.582707] CR2: 0000000000000080 [ 32.586236] ---[ end trace baae330eb22b1c0b ]--- [ 32.590986] Kernel panic - not syncing: Fatal exception [ 32.596655] Dumping ftrace buffer: [ 32.600175] (ftrace buffer empty) [ 32.603858] Kernel Offset: disabled [ 32.607471] Rebooting in 86400 seconds..