Re: [PATCH net-next 0/2] net: dsa: fix host fdb refcount when an entry roams

[Julius Bairaktaris]

> - How the issue was discovered, e.g. hit in production, hit during
>   development, syzbot report, manual code inspection, LLM or static
>   analysis tool scan.

Hit during development on a Xiaomi AX3600 (IPQ8074) running OpenWrt's
qca-ppe DSA switch driver. A station roaming between a DSA user port
and a Wi-Fi AP port of the same bridge logged

  qca-ppe 3a000000.ppe: port 5 failed to delete 02:5a:0b:a2:1a:46 vid 0 from fdb: -2

3-6 times per address when the two ports received on different CPUs,
and not at all when they shared one CPU (4 runs each). The dsa_loop
harness described in the cover letter reproduces it on net-next.

Julius