NXP frdm-rw612 does not work with mdns-responder sample application

[jukkar]

Describe the bug

There was report in Discord that mdns-responder did not work with NXP frdm-rw612 board when both Ethernet and wifi interfaces were enabled.
https://discord.com/channels/720317445772017664/1329476316650803253/1329479451104514059

When trying this, I noticed that if I enable NXP wifi CONFIG_WIFI_NXP=y, then the mdns-responder did not work as expected even when using Ethernet connection only. After investigating this, it seems that the either network poll or kernel k_poll does not notice that network internal receive queue contains received UDP packets which then leads to net_pkt resource exhaustion because the internal queue is not read and the received UDP packets stays there forever.

I tried this with nucleo_f767zi/stm32f767xx and did not see issues. Also there is no issue with frdm_rw612/rw612 board if NXP wifi is disabled.

To Reproduce
Building the sample with this

west build -p -b frdm_rw612/rw612 -d ../build/test samples/net/mdns_responder -- \
-DCONFIG_LOG_MODE_IMMEDIATE=y \
-DCONFIG_NET_SOCKETS_SERVICE_STACK_SIZE=2048 \
-DCONFIG_NET_MGMT_EVENT_QUEUE_SIZE=25 \
-DCONFIG_NET_MGMT_EVENT_STACK_SIZE=4096 \
-DCONFIG_MAIN_STACK_SIZE=8192 \
-DCONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096 \
-DCONFIG_HEAP_MEM_POOL_SIZE=122880 \
-DCONFIG_NET_TCP_WORKQ_STACK_SIZE=8192 \
-DCONFIG_NET_TX_STACK_SIZE=4096 \
-DCONFIG_NET_RX_STACK_SIZE=4096 \
-DCONFIG_NET_IF_MCAST_IPV4_ADDR_COUNT=5 \
-DCONFIG_NET_PKT_RX_COUNT=30 \
-DCONFIG_NET_PKT_TX_COUNT=30 \
-DCONFIG_NET_BUF_RX_COUNT=90 \
-DCONFIG_NET_BUF_TX_COUNT=90 \
-DCONFIG_NET_IPV4_IGMP=y \
-DCONFIG_NET_BUF_POOL_USAGE=y \
-DCONFIG_NET_LOG=y \
-DCONFIG_NET_IF_LOG_LEVEL_DBG=n \
-DCONFIG_DNS_SOCKET_DISPATCHER_LOG_LEVEL_DBG=y \
-DCONFIG_NET_SOCKETS_LOG_LEVEL_DBG=y \
-DCONFIG_NET_L2_ETHERNET_LOG_LEVEL_DBG=y \
-DCONFIG_NET_CONN_LOG_LEVEL_DBG=y \
-DCONFIG_NET_CONTEXT_LOG_LEVEL_DBG=y \
-DCONFIG_NET_TCP_LOG_LEVEL_DBG=n \
-DCONFIG_NVS_LOG_LEVEL_DBG=n \
-DCONFIG_MDNS_RESPONDER_LOG_LEVEL_DBG=y \
-DCONFIG_DNS_RESOLVER_LOG_LEVEL_DBG=y \
-DCONFIG_MDNS_RESPONDER=y \
-DCONFIG_MDNS_RESPONDER_DNS_SD=y \
-DCONFIG_DNS_SD=y \
-DCONFIG_DNS_RESOLVER=y \
-DCONFIG_ZVFS_POLL_MAX=18 \
-DCONFIG_NET_HOSTNAME_ENABLE=y \
-DCONFIG_NET_HOSTNAME_UNIQUE=n \
-DCONFIG_NET_HOSTNAME="\"zephyrtest\"" \
-DCONFIG_NET_SOCKETS_POLL_MAX=6 \
-DCONFIG_LLMNR_RESPONDER=y \
-DCONFIG_NET_CONFIG_MY_IPV4_ADDR="\"\"" \
-DCONFIG_NET_CONFIG_PEER_IPV4_ADDR="\"\"" \
-DCONFIG_NET_CONFIG_MY_IPV6_ADDR="\"\"" \
-DCONFIG_NET_CONFIG_PEER_IPV6_ADDR="\"\"" \
-DCONFIG_NET_DHCPV4=y \
-DCONFIG_NET_L2_WIFI_SHELL=y \
-DCONFIG_WIFI=y \
-DCONFIG_WIFI_NXP=y

and then flash

west flash -d ../build/test

Expected behavior
The sample should work regardless of whether CONFIG_WIFI_NXP is set or not. In the test I was not even using Wi-Fi connection but Ethernet only.
To test this, one can send a mDNS query like this from Linux host

nmap --script=dns-service-discovery -p 5353 zephyrtest.local

If using wireshark, one should be able to see a reply from zephyr to the mDNS query.

Impact
I am not saying the issue is in the NXP wifi driver, but clearly it is causing some effect in the system. As I am not familiar with the NXP wifi driver, I am assigning this to NXP for a time being.

Environment (please complete the following information):

I am in zephyr upstream commit 8b987d9