wpa_supplicant does not reassociate after reloading wifi driver

[svenmeier]

Background information:
I'm investigating problems with suspend from resume and my wifi driver rtl8723be. For this I added my wifi module to SUSPEND_MODULES in /etc/pm/config.d/modules. What I noticed is that after reloading of the module on suspend, wpa_supplicant is not able to associate with the network.

To identify the reason of this bug I stopped network-manager and started wpa_supplicant from the terminal:

$ sudo wpa_supplicant -dd -i wlan0 -c wpa.conf

Log of successful association with network is attached (wpa_supplicant_connect.log)

Then I unloaded the wifi driver:

$ sudo modprobe -rv rtl8723be

Log of the following disconnect is attached (wpa_supplicant_disconnect_after_unload.log)

Then I reloaded the wifi driver:

$ sudo modprobe -v rtl8723be

Log of failing wpa_supplicant is attached (wpa_supplicant_fails_after_reload.log)

After stopping wpa_supplicant and restarting it, it successfully associates with the network again.

Note that this is independent of the used wifi driver, as I was able to reproduce the problem on another machine with iwlwifi too.
Installing version 2.3 of wpasupplicant didn't help.

$ lsb_release -rd
Description: Ubuntu 14.10
Release: 14.10

$ apt-cache policy wpasupplicant
wpasupplicant:
  Installed: 2.3-1
  Candidate: 2.3-1
  Version table:
 *** 2.3-1 0
        100 /var/lib/dpkg/status
     2.1-0ubuntu4 0
        500 http://archive.ubuntu.com/ubuntu/ utopic/main amd64 Packages