Access points may unexpectedly experience "assert" kernel panics, with messages similar to the following in the log:
<0>[08/26/2020 05:37:30.4580] Kernel panic - not syncing: assert:"SCB_PS(scb) || wlc_twt_scb_active(wlc->twti, scb)" failed: file "wlc_apps.c:1808"
<0>[11/02/2020 03:17:07.1800] Kernel panic - not syncing: assert:"0" failed: file "wlc_twt.c:3042"
Conditions:
Access point is a 9105, 9115 or 9120 series.
Target Wait Time (TWT) is enabled (as it is by default.)
Workaround:
Disable TWT support on the WLAN(s):
AireOS:
config wlan target_waketime disable
IOS-XE (conf-wlan mode):
no dot11ax target-waketime
no dot11ax twt-broadcast-support
Further Problem Description:
Although these access points do not support the TWT feature, it was accidentally enabled by default.
This bug CSCvv51321 addresses the problem by ensuring that TWT is disabled on 9105/9115/9120
series APs, regardless of the controller configuration.