Hi, I'm reporting a regression in wireless functionality that appeared starting with kernel v6.9.0. The issue affects monitor mode frame injection when an AP interface is already active. Description: Monitor mode packet injection fails when performed on a virtual monitor interface created while the physical interface is running in AP mode. This worked correctly in all kernel versions up to v6.8.x but fails starting from v6.9.0. A maintainer of the rtw88 repository hinted that the issue might originate from the following commit. After compiling and testing the parent commit, I can confirm that the issue appears to originate from following commit. * Commit: wifi: mac80211: simplify non-chanctx drivers · torvalds/linux@0a44dfc " wifi: mac80211: simplify non-chanctx drivers" * URL: https://github.com/torvalds/linux/commit/0a44dfc070749514b804ccac0b1fd38718f7daa1 Reproduction Steps: 1. Configure AP mode on wlan0 using hostapd 2. Create a virtual monitor interface: iw dev wlan0 interface add wlan0mon type monitor addr 12:34:56:78:AB:CD 3. Test frame injection with your preferred method aireplay-ng -9 wlan0mon Results: Working behavior (≤v6.8): 23:58:12 Trying broadcast probe requests... 23:58:12 Injection is working! 23:58:14 xx:xx:xx:xx:xx:xx - channel: 1 - 'xxxxxxx' 23:58:20 30/30: 100% 23:58:20 xx:xx:xx:xx:xx:xx - channel: 1 - 'xxxxxxx' 23:58:21 Ping (min/avg/max): 4.066ms/27.308ms/170.734ms Power: -24.87 23:58:21 30/30: 100% Broken behavior (≥v6.9): 23:58:12 Trying broadcast probe requests... 23:58:14 xx:xx:xx:xx:xx:xx - channel: 1 - 'xxxxxxx' 23:58:20 0/30: 0% 23:58:20 xx:xx:xx:xx:xx:xx - channel: 1 - 'xxxxxxx' 23:58:21 Ping (min/avg/max): 4.066ms/27.308ms/170.734ms Power: -24.87 23:58:21 0/30: 0% Kernel Testing Matrix: Working kernels: * linux-image-6.1.0-kali9-amd64 (6.1.27-1kali1) * linux-image-6.1.127-custom (6.1.127-1) * linux-image-unsigned-6.2.0-060200-generic * linux-image-unsigned-6.2.0-060200rc1-generic * linux-image-unsigned-6.3.0-060300-generic * linux-image-unsigned-6.4.0-060400-generic * linux-image-unsigned-6.5.0-060500-generic * linux-image-unsigned-6.6.63-060663-generic * linux-image-unsigned-6.7.10-060710-generic * linux-image-unsigned-6.8.12-060812-generic Broken kernels: * linux-image-unsigned-6.9.0-060900-generic * linux-image-unsigned-6.9.10-060910-generic * linux-image-amd64/kali-rolling (6.11.2-1kali1) * linux-image-unsigned-6.12.0-061200-generic * linux-image-6.12.13-amd64 * linux-image-6.12.20-amd64 * linux-image-6.12.25-amd64 * linux-image-6.13.1/bookworm (6.13.1-1) * linux-image-6.14.0 * linux-image-6.14.5 * linux-image-6.15.1-toeirei * linux-image-6.15.3-toeirei Additional Information: This regression is not limited to the specific scenario described above. The issue affects multiple interface combinations: - Creating a monitor interface while the physical interface runs in AP mode (as described) - Creating an AP interface on a VIF while the physical interface is in monitor mode, then attempting injection on the physical interface - Using the physical interface in client mode with a monitor VIF - injection fails in this configuration as well Please let me know if you need additional debugging information, logs, or testing. Best regards i486
