Merge branch 'ip6_gre-Fixes-in-headroom-handling'
Petr Machata says:
====================
net: ip6_gre: Fixes in headroom handling
This series mends some problems in headroom management in ip6_gre
module. The current code base has the following three closely-related
problems:
- ip6gretap tunnels neglect to ensure there's enough writable headroom
before pushing GRE headers.
- ip6erspan does this, but assumes that dev->needed_headroom is primed.
But that doesn't happen until ip6_tnl_xmit() is called later. Thus for
the first packet, ip6erspan actually behaves like ip6gretap above.
- ip6erspan shares some of the code with ip6gretap, including
calculations of needed header length. While there is custom
ERSPAN-specific code for calculating the headroom, the computed
values are overwritten by the ip6gretap code.
The first two issues lead to a kernel panic in situations where a packet
is mirrored from a veth device to the device in question. They are
fixed, respectively, in patches #1 and #2, which include the full panic
trace and a reproducer.
The rest of the patchset deals with the last issue. In patches #3 to #6,
several functions are split up into reusable parts. Finally in patch #7
these blocks are used to compose ERSPAN-specific callbacks where
necessary to fix the hlen calculation.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
