Hi Steffen. On Thu, Dec 19, 2024 at 04:02:30PM +0100, Steffen Moser wrote: > Hello everyone, > > I've encountered a possible issue in a DD-WRT [1] setup where broadcast > packets stop being delivered after a GTK (Group Temporal Key) exchange. This > issue occurs on a system with the following hardware: > > Access Point Hardware: DynaLink DL-WRX36 > Router Software: DD-WRT v3.0-r58819 std (12/13/24) > CPU: Qualcomm IPQ8072A > WiFi Chips: Qualcomm QCN5024 and Qualcomm QCN5054 > WiFi Driver: ath11k > Firmware: WLAN.HK.2.12-01460-QCAHKSWPL_SILICONZ-1 > NSS FW version: NSS.FW.12.5-210-HK.R > Kernel: Linux WL-AP-EG 6.6.64-rt29 #1791 SMP Thu Dec 12 16:41:51 +07 > 2024 aarch64 DD-WRT > > The behavior is such that after a GTK exchange, the AP can get into a "weird > state". When being there, broadcast frames like ARP or mDNS are no longer > reliably delivered to connected clients while unicasts come still through. > In this "weird state", the channel quality (active time vs. busy time) goes > down and latencies to the still reachable WIFI clients rise. This looks a lot like an issue we hit a while back. There is this patch [0] from Qualcomm's wlan-open repository. It is a revert of [1]. Using that the issue was never reproduced. Maybe this can help. Also adding ath11k list. Regards. -- Remi [0]: https://git.codelinaro.org/clo/qsdk/oss/system/feeds/wlan-open/-/blob/win.wlan_host_opensource.3.0.r24/patches/ath11k/350-ath11k-Revert-clear-the-keys-properly-when-DISABLE_K.patch [1]: commit 436a4e886598 ("ath11k: clear the keys properly via DISABLE_KEY") > > I've come across a related bug report on GitHub that describes a similar > issue: > https://github.com/openwrt/openwrt/issues/9555#issuecomment-2433857175 > > Unfortunately, the GitHub discussion drifted towards various other possible > bugs. > > In the meantime, I have a done a lot of additional debugging, but I am > coming to a dead end due to limited knowledge of the ath11k driver and > firmware internals. Interestingly, the AP can get back from "weird state" to > "normal state" after another GTK rekey event. I've seen this behavior only > in the 5 GHz band, yet (using non-DFS-channels). > > My questions to the Linux wireless experts and developers in this community: > > · Is such a behavior known with ath11k on IPQ8072A or on the mentioned WiFi > chips (QCN5024/QCN5054)? > > · Could this be a driver or firmware issue that specifically arises after a > GTK or even GMK exchange? > > · What can I do to debug it further? I've switched on debugging in > "hostapd" in order to see the keying events. Are there more lower-level logs > I can get from the WiFi chip and match to the latency and key exchange > observations? > > · Are there any additional information I can/should deliver to give the > devs more insight about this issue? > > When exchanging the DynaLink DL-WRX36 AP by a Netgear R7800 AP (CPU: QCA > IPQ8065), its predecessor, the problem is gone without touching any of the > clients. > > Thank you in advance for any insights or experiences regarding this issue. > > Best regards, > Steffen > > [1] https://dd-wrt.com/ > > > -- > ✂----------------------------------------------------------------------- > Dipl.-Inf. Steffen Moser Tel (Office): +49.731.50.32407 > School of Advanced Professional Studies Ulm University, Room: 1013 > https://wissenschaftliche-weiterbildung.org/ Oberberghof 7, 89081 Ulm > https://saps.uni-ulm.de/ Germany >
