From: David S. Miller Date: Thu, 17 May 2018 20:50:20 +0000 (-0400) Subject: Merge branch 'ip6_gre-Fixes-in-headroom-handling' X-Git-Tag: v4.17-rc7~27^2~9 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=374edea4aaedb92964d35f68318c094b6d5c0f63;p=linux.git 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 --- 374edea4aaedb92964d35f68318c094b6d5c0f63