Re: Question: bridge: clarify MST VLAN list RCU traversal contract

Runyu Xiao <[email protected]> Fri, 3 Jul 2026 12:24:22 +0800 (GMT+08:00)

Newsgroups	gmane.linux.network.bridge
Message-ID	<AMAAoQBgKr7QFadsWSye64o0.3.1783052662261.Hmail.220255722__39951.079971955$1783065721$gmane$org@seu.edu.cn>

Hi Ido,

On Sun, 28 Jun 2026 20:49:00 +0300, Ido Schimmel wrote:
&gt; I don't think anything needs to change. AFAICT, br_mst_info_size() is
&gt; only reachable via the get_link_af_size() callback and
&gt; rtnl_link_get_af_size() always invokes it from an RCU read-side critical
&gt; section.
&gt;
&gt; Did you see a splat with CONFIG_PROVE_RCU_LIST?
Thanks for the clarification.

No, I did not see an in-kernel splat from the actual rtnetlink path.
The warning I had was from the reviewed out-of-tree reproducer used for
our CONFIG_PROVE_RCU_LIST triage, not from a real bridge netlink call
path.

Given your explanation that rtnl_link_get_af_size() already invokes
this from an RCU read-side critical section, I will treat this as an
intended contract and I will not pursue a patch for it based on the
current evidence.

Thanks,
Runyu