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Kernel version status

Greg Kroah-Hartman has released long-term kernel 3.0.22 and stable kernel 3.2.7. Earlier this week he published the stable kernel 3.2.8. Like the recent versions 3.0.20 and 3.2.5, this version also promises some changes that are a little bolder than usual. Kernel 3.2.8 does not resolve the power management problem, rather it rectifies a problem fixed in the recent fourth pre-release version of Linux 3.3, which resulted in occasional data transfer problems when using WPA2. The problem only arose when using a 32-bit kernel on an x86 processor with AES-NI support, and was the result of the kernel, in certain circumstances, failing to correctly restore the state of the floating point unit (FPU); some of the changes might also fix bugs found on x86-64 systems.

Not long after publishing 3.2.8, Kroah-Hartman published pre-releases of Linux 3.0.23 and 3.2.9 for review. The time frame set for comments ends on Thursday morning; the versions are likely to be released shortly after that.

Linus Torvalds has now issued the fifth pre-release version of Linux 3.3. In the release email, he notes that there is little to report with this version, adding that "maybe things are finally calming down".

Bug reporting

Rafael J. Wysocki recently posted two new regression reports, listing currently known regressions in the mainline tree. The first lists bugs which appear to have been caused by changes made between Linux 3.1 and 3.2, the second, bugs caused by changes made since 3.2. Until late summer 2011, regression reports were generally published weekly. As a result of the hack at kernel.org, however, the kernel bug tracking system (bugzilla.kernel.org) was offline for a prolonged period, hindering production of bug reports.

In one of the reports, Wysocki notes that he and his co-developers use Bugzilla to obtain an overview of known bugs and do not expect kernel developers to participate there. This may be a reaction to a Google+ post in which Greg Kroah-Hartman announced that he would no longer be using the bug database. Hartman expressed the view that the approach does not fit with the development flow and suggested that bugs and other problems should be dealt with via email. Some of the comments on his post note that information sent by email has a habit of being forgotten. Some developers, however, see this as a benefit – network subsystem maintainer David S. Miller noted "Important things will get retransmitted".

Conference videos

The Linux Foundation has posted videos of many of the presentations given at the recent Embedded Linux Conference (ELC) and Android Builders Summit (1, 2). IBM's Arnd Bergmann, who is involved in Linaro development, gave a presentation entitled ARM Subarchitecture Status, in which he provides some background information on the clean-up work, rewriting and modified work processes with which developers have been improving and intend to further improve ARM support in the kernel. This follows Linus Torvalds' outspoken complaint about the mess in the ARM community from a few months back. Bergmann mentions a whole series of improvements which have already been implemented, such as support for device trees in the ARM code, the first part of which was merged into Linux 3.0. There are also signs of a breakthrough in efforts to enable a single kernel binary (zImage) to be booted on a number of widely differing ARM platforms.

In his Managing Kernel Modules With kmod presentation, Lucas De Marchi outlines details of kmod, which already has replaced module-init-tools (which includes tools such as lsmod and modprobe) in some Linux distributions. In Automated Testing With ktest.pl, Red Hat developer Steve Rostedt explains how to use ktest.pl, a tool included with the kernel that is able to automate some test procedures. Rostedt is also the driving force behind tracing tool ftrace (function tracer), the subject of Kobayashi Yoshitake's presentation Ineffective and Effective Ways To Find Out Latency Bottlenecks With Ftrace, which explores how ftrace can be used to elucidate the causes of performance problems. As at many previous conferences, LWN.net editor and kernel developer Jon Corbert presented his famous Kernel Report, summarising recent developments in the Linux kernel.

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