APPLIED: [SRU][N][PATCH v2 0/1] qrtr: ns: node limit of 64 breaks QRTR routing on large multi-node deployments

[Stefan Bader]

On 28/08/2026 20:21, 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).
> 
> ---
> Changes in v2:
> - Fix formatting problems.
> - Match the comment and the limits macros to the order in the linux mainline
>    tree.
> - Address Rickey's comments.
> ---
> Youssef Samir (1):
>    net: qrtr: ns: Raise node count limit to 512
> 
>   net/qrtr/ns.c | 18 ++++++------------
>   1 file changed, 6 insertions(+), 12 deletions(-)
> 

Applied to noble:linux/master-next. Thanks.

-Stefan
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