Bug#836742: linux-image-4.7.0-1-amd64: PPTP VPN not working at all

[Zlatko Čalušić <zcalusic@bitsync.net>]

Package: src:linux
Version: 4.7.2-1
Severity: normal

PPTP VPN has stopped working in 4.7 kernel. Worked just fine in 4.6.

I did some limited debugging, without much success. It seems ppp_mppe
module is not loaded on demand, and also loading it manually doesn't
help at all. No errors in the kernel log. pppd reports LCP: timeout
sending Config-Requests and timeouts.

-- Package-specific info:
** Version:
Linux version 4.7.0-1-amd64 (debian-kernel@lists.debian.org) (gcc version 5.4.1 20160803 (Debian 5.4.1-1) ) #1 SMP Debian 4.7.2-1 (2016-08-28)

** Command line:
BOOT_IMAGE=/boot/vmlinuz-4.7.0-1-amd64 root=/dev/sda1 ro profile=2

** Not tainted

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.7.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: systemd (via /run/systemd/system)

Versions of packages linux-image-4.7.0-1-amd64 depends on:
ii  initramfs-tools [linux-initramfs-tool]  0.125
ii  kmod                                    22-1.1
ii  linux-base                              4.4

Versions of packages linux-image-4.7.0-1-amd64 recommends:
ii  firmware-linux-free  3.4
ii  irqbalance           1.1.0-2

Versions of packages linux-image-4.7.0-1-amd64 suggests:
ii  debian-kernel-handbook  1.0.17
ii  grub-pc                 2.02~beta2-36
pn  linux-doc-4.7           <none>

Versions of packages linux-image-4.7.0-1-amd64 is related to:
ii  firmware-amd-graphics     20160110-1
pn  firmware-atheros          <none>
pn  firmware-bnx2             <none>
pn  firmware-bnx2x            <none>
pn  firmware-brcm80211        <none>
pn  firmware-cavium           <none>
pn  firmware-intel-sound      <none>
pn  firmware-intelwimax       <none>
pn  firmware-ipw2x00          <none>
pn  firmware-ivtv             <none>
ii  firmware-iwlwifi          20160110-1
pn  firmware-libertas         <none>
ii  firmware-linux-nonfree    20160110-1
ii  firmware-misc-nonfree     20160110-1
pn  firmware-myricom          <none>
pn  firmware-netxen           <none>
pn  firmware-qlogic           <none>
ii  firmware-realtek          20160110-1
pn  firmware-samsung          <none>
pn  firmware-siano            <none>
pn  firmware-ti-connectivity  <none>
pn  xen-hypervisor            <none>

-- no debconf information