Wifi intermittently stops working since 15.04 upgrade

[halfbeing]

Since upgrading to 15.04 a couple of weeks ago I have been finding that sometimes my wifi completely stops working. Restarting network manager doesn't help, nor does removing and reinserting the wireless driver. I can get network access through an ethernet cable.

Another, possibly related problem I have been experiencing since upgrading to 15.04 is that sometimes wpa_supplicant starts hogging CPU, up to 100% on one core. When I kill it, the replacement instance of wpa_supplicant continues to hog the CPU. I am not sure whether this is caused by the same fault that is causing my wifi to fail. As I send this error report, my machine is in such a crippled state with no wifi and wpa_supplicant slowing everything to a crawl. I noticed that wpa_supplicant was misbehaving only after I had tried removing and reinserting the wifi driver, so I don't know whether the wifi failure problem caused wpa_supplicant to go bananas, or whether it was the fact that I had messed about with the driver.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: wpasupplicant 2.1-0ubuntu7.1
ProcVersionSignature: Ubuntu 3.19.0-18.18-lowlatency 3.19.6
Uname: Linux 3.19.0-18-lowlatency x86_64
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
CurrentDesktop: Unity
Date: Sun Jun 7 15:01:56 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-03-06 (93 days ago)
InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
SourcePackage: wpa
UpgradeStatus: Upgraded to vivid on 2015-05-29 (8 days ago)

[Launchpad Janitor (janitor)]

[Expired for wpa (Ubuntu) because there has been no activity for 60 days.]