On Mon, 11 Apr 2022 09:58:31 +0200 Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > On Mon, 2022-04-11 at 15:39 +0800, Mathy Vanhoef wrote: > > In the current hwsim config no rate control algorithm is enabled. > > This means that, when using defconfig-hwsim, the mac80211_hwsim > > fails to load with the following error: > > > > [ 132.155183] ieee80211 phy0: Failed to select rate > > control algorithm [ 132.155196] ieee80211 phy0: Failed to > > initialize rate control algorithm > > > > Fix this by enabling rate control algorithms in the provided hwsim > > config. > > Makes sense, thanks. > > > Experiments were also less reliable when WEXT was enabled. So this > > patch also disables WEXT when using defconfig-hwsim to make the > > default more reliable for users. > > > > Huh? How so? Maybe some other tool was present on the system that was > using wext, and disabling wext made that tool no longer detect the > wireless or so? I cannot see how else it would be "less reliable" with > wext enabled, if you don't really use it. I checked this in more detail: when using kernel 5.13.0-30-generic on Ubuntu 20.04 with backports-5.15.5-1 the kernel crashes when adding interfaces in case WEXT has been enabled in backports (in my case when inserting mac80211_hwsim in a virtual machine). The problem is that wdev->netdev is NULL inside the function cfg80211_init_wdev, causing the kernel to hang. The same happens on kernel 5.15.40-1-lts on Arch Linux (this is currently the most up-to-date LTS kernel on Arch Linux). Interestingly, on kernel 5.13.0-41-generic on Ubuntu 20.04 this isn't a problem because the field wdev->netdev is then initialized. -- To unsubscribe from this list: send the line "unsubscribe backports" in
