wpa_supplicant 2.12 CONFIG_NAN_USD=y dropped packets

smash · Today 09:02:11

TLDR:

wpa_supplicant 2.12 started including `CONFIG_NAN_USD=y` where 2.11 did not. Since upgrading to 2.12 I have an issue where after approximately 5 minutes packets are lost and the state is never recovered leading to a 50% speed drop on WiFi until the stack is reset. Through testing I have narrowed this down to `CONFIG_NAN_USD` but have not bisected the code to determine exactly where this is occurring. I am hoping someone more familiar with the code would know or at least reduce the amount of work I'd need to do to find out as I'm disabled and this kind of thing takes me a very long time.

I've been waiting for account approval on gitlab to be able to report this directly to the package maintainer but think it's important it is addressed sooner rather than later. Also please excuse the use of AI to generate this summary - I have only done so due to accessibility requirements.

Summary

On a Dell XPS 9575 laptop using a Qualcomm Atheros QCA6174 Wi-Fi adapter (`ath10k_pci`), Wi-Fi performance can degrade after a short period after the connection is established. The degradation can persist until the wireless interface is reset by toggling the laptop's wireless hardware switch, but inevitably reoccurs again after several minutes.

The problem is reproducible with the distribution's `wpa_supplicant` 2.12 package and does not occur in the same persistent form with version 2.11.

Testing custom builds of hostap/wpa_supplicant 2.12 has isolated `CONFIG_NAN_USD=y` as a sufficient trigger for the problem in the tested build configuration. Disabling this option avoids the failure under otherwise matching build settings.

I have not yet identified the exact source-code change or mechanism responsible.

Environment

- Laptop: Dell XPS 9575 2-in-1
- Wireless adapter: Qualcomm Atheros QCA6174, PCI ID `168c:003e`, revision 32
- Subsystem: Rivet Networks / Killer 1435, ID `1a56:143a`
- Kernel driver: `ath10k_pci`
- Interface: `wlp2s0`
- Distribution: Manjaro Linux Testing (Also confirmed on Archlinux)
- Kernel versions tested: 6.18, 6.19 and 7.3; the issue was not resolved by changing kernels
- Affected supplicant package: `wpa_supplicant` 2:2.12-1
- Comparison working package: `wpa_supplicant` 2:2.11-3
- Network management: NetworkManager, using the D-Bus/systemd-managed wpa_supplicant service

The wireless network is 5 GHz, using an 80 MHz channel. Signal strength during testing was approximately -48 dBm.

Symptoms

After the Wi-Fi connection has been established in approximately two minutes network performance always deteriorates. Downloads and external speed tests show substantially reduced throughput related to packet loss that persists rather than recovering normally.

Toggling the laptop's wireless hardware switch off and then back on restores normal performance. As does issuing `nmcli connection up "wifi_name"`.

The failure is not limited to one kernel version. Downgrading NetworkManager alone did not resolve it.

The `ath10k` firmware crash counter remained at zero during the investigation.

Reproduction and build-configuration tests

The issue is reproducible with the distribution's wpa_supplicant 2.12 package and was not observed in the same persistent form with version 2.11.

To isolate the cause, I built hostap/wpa_supplicant 2.12 from source and tested different compile-time configurations. The tests used the same test setup and otherwise matching configuration settings, with the relevant option changed between builds.

The following results were observed:

Build configuration
1. Minimal test configuration with the additional features disabled = No persistent degradation observed
2. `CONFIG_NAN_USD=y`, with `CONFIG_PASN=y` and `CONFIG_PR=y` retained = Original degradation reproduced
3. `CONFIG_NAN_USD` disabled again, with the other settings unchanged = No persistent degradation observed

The `CONFIG_NAN_USD=y` build had SHA-256:
`d9238ce22c43cb4752fbbef0e731048c8e6b584121014874a2f2cc7e11a05d03`

The otherwise matching build with `CONFIG_NAN_USD` disabled had SHA-256:
`2004011ae88a7a77c6b470e8a596fd7fa871540db9095bce6533735734b35acb`

Additional tests individually enabling `CONFIG_SAE_PK`, `CONFIG_DPP3`, `CONFIG_HE_OVERRIDES`, `CONFIG_IEEE80211AX` and `CONFIG_IEEE80211BE` did not reproduce the persistent degradation when `CONFIG_NAN_USD` was disabled in the tested configurations.

The tests do not establish whether the problem is in NAN USD code itself, a shared code path affected by this build option, or an interaction with the driver.

What I am asking

Could the maintainers investigate why enabling `CONFIG_NAN_USD` in wpa_supplicant 2.12 appears to trigger this Wi-Fi performance regression with the QCA6174 / ath10k driver?

I can provide the custom build configurations, source revisions, test binaries' hashes, and further diagnostic output if useful.

I have not yet completed a source-level bisect of the changes related to NAN USD between hostap 2.11 and 2.12.

Lone_Wolf · Today 11:37:48

On archlinux the last 2.11 version of hostapd was 2.11-4 while wpa_supplicant was 2:2.11-6 .

Have you tested with those exact versions on an archlinux installation ?
Please post logs of your tests on an uptodate archlinux installation.

Moderator Note
Moving to Networking, Server, and Protection

Last edited by Lone_Wolf (Today 11:38:07)

Arch Linux

#1 Today 09:02:11