Netdev List
 help / color / mirror / Atom feed
From: Nikolay Aleksandrov <razor@blackwall.org>
To: netdev@vger.kernel.org
Cc: idosch@nvidia.com, davem@davemloft.net, edumazet@google.com,
	kuba@kernel.org, pabeni@redhat.com, horms@kernel.org,
	roopa@nvidia.com, bridge@lists.linux.dev, andrew+netdev@lunn.ch,
	dlstevens@us.ibm.com, amwang@redhat.com,
	Nikolay Aleksandrov <razor@blackwall.org>
Subject: [PATCH net 0/2] bridge/vxlan: fix reading neigh ha without synchronization
Date: Mon, 17 Aug 2026 17:36:11 +0300	[thread overview]
Message-ID: <20260817143613.685769-1-razor@blackwall.org> (raw)

Hi,
Neigh ha address must be read using the seqlock to get a stable snapshot.
Both the bridge and vxlan read it directly and can see partial updates.
I reproduced both issues with running neigh updates and exercising these
paths in parallel and saw partial addresses, e.g. updating between
neigh A: 02:00:00:00:00:00 neigh B: fe:ff:ff:ff:ff:ff was able to observe
02:00:ff:ff:ff:ff and fe:ff:00:00:00:00 in packets. Noticed this initially
in the bridge, then checked vxlan and its arp/neigh_reduce functions have
the same bug, route_shortcircuit is doing the right thing already.

Cheers,
 Nik

Nikolay Aleksandrov (2):
  net: bridge: arp/nd proxy: fix reading neigh ha
  vxlan: fix reading neigh ha

 drivers/net/vxlan/vxlan_core.c | 20 +++++++++++++-------
 net/bridge/br_arp_nd_proxy.c   | 24 ++++++++++++++----------
 2 files changed, 27 insertions(+), 17 deletions(-)

-- 
2.47.3


             reply	other threads:[~2026-08-17 14:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-17 14:36 Nikolay Aleksandrov [this message]
2026-08-17 14:36 ` [PATCH net 1/2] net: bridge: arp/nd proxy: fix reading neigh ha Nikolay Aleksandrov
2026-08-17 14:36 ` [PATCH net 2/2] vxlan: " Nikolay Aleksandrov
2026-08-17 15:25 ` [PATCH net 0/2] bridge/vxlan: fix reading neigh ha without synchronization Nikolay Aleksandrov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260817143613.685769-1-razor@blackwall.org \
    --to=razor@blackwall.org \
    --cc=amwang@redhat.com \
    --cc=andrew+netdev@lunn.ch \
    --cc=bridge@lists.linux.dev \
    --cc=davem@davemloft.net \
    --cc=dlstevens@us.ibm.com \
    --cc=edumazet@google.com \
    --cc=horms@kernel.org \
    --cc=idosch@nvidia.com \
    --cc=kuba@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=pabeni@redhat.com \
    --cc=roopa@nvidia.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox