On 8/3/20 6:50 PM, Simon Matter via CentOS wrote: >> Hi, >> >> I've got a task to have a small number of laptops netboot Linux over >> WiFi. The kernel is loaded off the USB stick of cource, it's off topic >> for now. >> >> The WPA-supplicant daemon is started early by dracut off initrd. It >> works. Mostly. >> >> The problem is that upon shutdown systemd terminates all the processes >> FIRST and unmounts filesystems NEXT. >> >> Guess what? Upon termination, wpa-supplicant brings the wireless >> interface down and the system hangs being unable to unmount now-defunct >> NFSroot. > Short answer: > > Looks like this should be fixed in systemd or its configuration. > > Long answer is the one I already gave you on centos-devel. I post it here > because someone may have deeper knowledge of what exactly goes on: > > What I'm wondering here is, do you see the hangs because of wpa_supplicant > was terminated and therefore also the wireless interface is down, or do > you see the hangs because networking is already completely down. It's because of wpa_supplicant. When I run the same config over wired network, it shuts down gracefully. A dirty solution I found is to kill (-9) wpa_supplicant daemon right before shutdown. WiFi keeps running for a second it requires to do a graceful NFS unmount. Best regards, Dmitry Mikhailov