Cisco VPN Client, Ralink Wi-Fi Drivers and Random Kernel Panics

A client came in recently with a series of odd, apparently unpredictable kernel panics. A few minute of log trolling led to four panic logs. Knowing that she’d installed Ralink USB Wi-Fi device drivers on the machine under Snow Leopard, I initially suspect them as the root cause (I’ve never liked Ralink’s ugly, kludgy software, and tend to suspect it on principle.)

Two logs showed a crash on loading Airport extensions, and two on USB drivers, but the common link was the extension loaded just prior…in each case, a kext for Cisco’s VPN client. This surprised me not just because I’d expected to find the Ralink stuff, but because we switched from the Cisco native VPN client to AnyConnect over a year ago. Apparently, a significant portion of the old VPN client had remained on her system, and been carried forward through at least one upgrade cycle.

A check of the /private/var/opt/ subdirectory showed most of the client still around. Running the vpn_unintall script removed most of the bits (which I double-checked by visiting each location specified in the script. I then manually delete the cisco_vpn subdirectory in opt. I also removed the Ralink utilities, including a preferences file in /Library/Preferences and a directory in /Library/Frameworks. Ralink provides no uninstaller.

So far, no more kernel panics. Possibly my distaste for both Cisco’s VPN client and Ralink’s just is justified.

UPDATE: This situation is a good argument for keeping a copy of John Welch’s Kext Lister utility handy.

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