Comment 9 for bug 1415880

Brian Burch (brian-pingtoo) wrote :

I need advice on whether I should be opening a new bug, or is it OK to stay with this one?

On further investigation, I have noticed three things:

1. The current trusty repository bcmwl-kernel-source 6.30.223.141+bdcom-0ubuntu2 is used on my wife's laptop. This system is not experiencing null pointer crashes OR Scan_results errors. This evidence strongly suggests both problems were introduced with 6.30.223.248+bdcom-0ubuntu1.

2. On checking syslog carefully, the Scan_results errors are often associated with the system running slowly and "[TTM] Out of kernel memory" messages being logged. The "victim" is the ATI radeon drm driver, but I suspect the bcmwl scan errors are causing the driver to not release kernel memory it has used for its wlan scan. Usually, I have to reboot the system to restore normal performance. I have attached an appropriate syslog extract. (note: when searching for these display-related messages I hit very old bugs that were never explicitly resolved).

3. I turned wifi off 12 hours ago and have been running the system via its ethernet adapter (incidentally, also from Broadcom). Syslog doesn't contain ANY "out of kernel memory" errors and system performance is back to normal and stable.