random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) urandom_read: 1 callbacks suppressed random: sshd: uninitialized urandom read (32 bytes read) BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1765 PGD 1b7f01067 [ 21.931060] PUD 1ca58c067 Oops: 0002 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 3793 Comm: syz-executor083 Not tainted 4.9.122-g54068d6 #78 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801b7726000 task.stack: ffff8801b5fa8000 RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1765 RSP: 0018:ffff8801b5fafca0 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff8801b5ed9680 RCX: 0000000000000000 RDX: 1ffff10036b9c300 RSI: ffffffff836c39a1 RDI: ffff8801b5ce1800 RBP: ffff8801b5fafcc0 R08: ffff8801b77268e8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801b5ce1680 R13: ffff8801b5ed9688 R14: 0000000000000000 R15: ffffffff83019be0 FS: 00000000020c0880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 00000001cb18e000 CR4: 00000000001606f0 Stack: ffff8801b5cf3b80 ffff8801b5ed9680 ffff8801b5cf3f50 ffff8801b5cf3e58 ffff8801b5fafce8 ffffffff836cb2b2 ffff8801b5cf3fc0 ffff8801b5cf3b80 ffffffff836cb1e0 ffff8801b5fafd20 ffffffff830270f5 ffff8801b5cf3fc0 Call Trace: [] l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:297 [inline] [] pppol2tp_session_destruct+0xd2/0x110 net/l2tp/l2tp_ppp.c:460 [] __sk_destruct+0x55/0x590 net/core/sock.c:1428 [] sk_destruct+0x63/0x80 net/core/sock.c:1463 [] __sk_free+0x4f/0x220 net/core/sock.c:1471 [] sk_free+0x2b/0x40 net/core/sock.c:1482 [] sock_put include/net/sock.h:1588 [inline] [] pppol2tp_release+0x239/0x2e0 net/l2tp/l2tp_ppp.c:501 [] sock_release+0x96/0x1c0 net/socket.c:600 [] sock_close+0x16/0x20 net/socket.c:1047 [] __fput+0x263/0x700 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10c/0x180 kernel/task_work.c:116 [] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [] exit_to_usermode_loop+0xfc/0x120 arch/x86/entry/common.c:161 [] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline] [] syscall_return_slowpath arch/x86/entry/common.c:260 [inline] [] do_syscall_64+0x364/0x490 arch/x86/entry/common.c:287 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb 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 RIP [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1765 RSP CR2: 0000000000000080 ---[ end trace 4b8b8d59fc02d1c6 ]---