Eric Dumazet 28afc87bd8 macvlan: inherit needed_headroom and needed_tailroom from lowerdev
[ Upstream commit cef51860be ]

macvlan devices inherit hard_header_len from lowerdev during macvlan_init(),
but leave needed_headroom and needed_tailroom set to 0.

When the underlying lowerdev requires extra headroom or tailroom for
headers/trailers (e.g. macsec, ipsec, wireguard, tunnels, or veth with rx
headroom), upper layers calculating packet headroom and tailroom fail to
reserve sufficient space.

This can result in reallocation overhead, skb headroom underflows, or KASAN
slab-use-after-free crashes when dev_hard_header() / macvlan_hard_header()
prepends header data or when lower devices append tailroom.

Fix this by:
1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init().
2. Propagating needed_headroom and needed_tailroom updates to attached macvlans
   in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events.

Fixes: b863ceb7dd ("[NET]: Add macvlan driver")
Reported-by: Tangxin Xie <xietangxin@h-partners.com>
Closes: https://lore.kernel.org/netdev/CANn89i+1EW-sFNK8xoq98gMbPCeLS7e=+rs9gHfLg5Wj+4x0sw@mail.gmail.com/T/#m16adf0ff972cbfd8066c3a8e656e75eaeb12d021
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Hangbin Liu <liuhangbin@kylinos.cn>
Link: https://patch.msgid.link/20260806141938.287660-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-08-23 14:20:05 +02:00
2026-08-23 14:20:05 +02:00
2026-05-23 13:03:09 +02:00
…
2026-08-03 11:15:40 +02:00
…
…
…
…
…
2026-05-23 13:03:09 +02:00
2026-08-19 18:13:14 +02:00
…

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
S
Description
No description provided
Readme
5.7 GiB
Languages
C 96.9%
Assembly 0.9%
Rust 0.6%
Shell 0.6%
Python 0.5%
Other 0.3%