NACK/Cmnt: [SRU][J][PATCH 0/1] qrtr: ns: node limit of 64 breaks QRTR routing on large multi-node deployments

[Edoardo Canepa]

Rejected for the following reasons:
superseded,alreadyappliedthroughthev5.15.216stableupdate:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2165192

On 8/28/26 23:26, Youssef Samir wrote:
> BugLink:https://bugs.launchpad.net/bugs/2165140
>
> SRU Justification:
>
> [Impact]
>
>   * Commit 27d5e84e810b ("net: qrtr: ns: Limit the total number of nodes")
>     introduced a hard cap of 64 on the number of QRTR nodes the namespace
>     server (qrtr_ns) will track, including the host node itself.
>     That limit was set as a DoS mitigation but is too low for legitimate
>     large-scale deployments, such as Qualcomm AI200 systems, which register
>     up to 384 QRTR nodes across their SoCs/cards.
>
>   * This patch fixes this issue by increasing the limit to 512.
>
>   * This patch should be backported because it affects deployments with 64
>     or more Qualcomm AI100/AI200 targets.
>
> [Fix]
>
>   * Backport of upstream commit:
>     ff194cffd586 ("net: qrtr: ns: Raise node count limit to 512")
>
> [Test Plan]
>
>   * Checking dmesg on an Ubuntu 24.04 system with at least 6.8.0-136-generic,
>     having at least 64 remote QRTR nodes, it will show "QRTR clients exceed max
>     node limit!" for every extra node.
>   * Also, by running a QRTR client then sending a QRTR_TYPE_NEW_LOOKUP packet,
>     only 64 nodes will show up (63 remote node + the local node).
>   * After applying the fix, dmesg should no longer show the error message, and
>     the lookup client will return a full list of nodes.
>
> [Where problems could occur]
>
>   * If a deployment exceeds 512 nodes, the original symptom returns identically
>     (same log message, same rejection behavior).
>
> Youssef Samir (1):
>    net: qrtr: ns: Raise node count limit to 512
>
>   net/qrtr/ns.c | 31 +++++++++++++++++++------------
>   1 file changed, 19 insertions(+), 12 deletions(-)
>
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