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GCC Compiler 4.3.0 exposes a Linux / BSD kernel bug

Since version 4.3, gcc changed its behavior concerning the x86/x86-64 ABI and the direction flag, that is it now assumes that the direction flag is cleared at the entry of a function and it doesn't clear once more if needed. According to LWN article GCC 4.3.0 exposes a kernel bug:

A change to GCC for a recent release coupled with a kernel bug has created a messy situation, with possible security implications. GCC changed some assumptions about x86 processor flags, in accordance with the ABI standard, that can lead to memory corruption for programs built with GCC 4.3.0. No one has come up with a way to exploit the flaw, at least yet, but it clearly is a problem that needs to be addressed.

=> GCC 4.3.0 exposes a kernel bug (via ./)

Red Hat Enterprise Linux 5.2 Beta Released

RHEL 5.2 beta has been released. Red Hat engineers backport many of the new features from later kernels to the Red Hat Enterprise Linux 5 kernel, such as support for new hardware and virtualization enhancements. This provides Red Hat Enterprise Linux subscribers with important new capabilities while maintaining stable application interfaces -- so that applications continue to run after new updates are installed. And, of course, it’s always worth repeating that updates, which are released about twice a year, are included with every Red Hat Enterprise Linux subscription.

This will give our you a chance to see what your systems will be running later this year. You can grab beta version from RHN.

=> Press Release : Red Hat Enterprise Linux 5.2 Beta

Find and Fix Linux Latency Problem with LatencyTOP Software

A TOP-like tool for monitoring system latency and its causes for Linux system.

The Intel Open Source Technology Center is pleased to announce the release of version 0.1 of LatencyTOP, a tool for developers to visualize system latencies. Skipping audio, slower servers, everyone knows the symptoms of latency. But to know what's going on in the system, what's causing the latency, how to fix it... that's a hard question without good answers right now.

LatencyTOP is a Linux tool for software developers (both kernel and userspace), aimed at identifying where in the system latency is happening, and what kind of operation/action is causing the latency to happen so that the code can be changed to avoid the worst latency hiccups.
Linux Latency Problem with LatencyTOP Software
(Fig. 01: LatencyTOP in Action [ Image Credit: Intel Corp. ])

Download LatencyTOP

=> Visit official project site to download LatencyTOP software. Please note that you also need to patch Linux kernel.

How to: Upgrade Fedora Linux From 32-bit System to 64-bit Version w/o Reinstalling Server

This small guide may come handy...

From the article:

One great thing about Linux is that you can transplant a hard disk from a machine that runs a 32-bit AMD XP processor into a new 64-bit Intel Core 2 machine, and the Linux installation will continue to work. However, if you do this, you'll be running a 32-bit kernel, a C library, and a complete system install on a processor that could happily run 64-bit code. You'll waste even more resources if your new machine has 4GB or more of system memory, and you'll be forced to either not use some of it or run a 32-bit Physical Address Extension (PAE) kernel. Cross-grading to the 64-bit variant of your Linux distribution can help you use your resources more wisely. A disclaimer: changing the architecture of your Fedora installation from 32 to 64-bit isn't recommended or supported in any way. Perform this at your own risk after creating a suitable backup.

=> Upgrade from 32-bit to 64-bit Fedora Linux without a system reinstall [linux.com]

Programming: Understanding Linux Completely Fair Scheduler

The new Linux scheduler extends scheduling capabilities by introducing scheduling classes and also simplifies debugging by improving schedule statistics. Completely Fair Scheduler (CFS) is getting good reviews when tested for thread-intensive applications including 3D games. CFS handles CPU resource allocation for executing processes, and aims to maximize overall CPU utilization while maximizing interactive performance. CFS considered as the first implementation of a fair queuing process scheduler in a widely used general-purpose operating system.

The Linux 2.6.23 kernel comes with a modular scheduler core and a CFS, which is implemented as a scheduling module. In this article, get acquainted with the major features of the CFS, see how it works, and look ahead to some of the expected changes for the 2.6.24 release.

=> Introducing the CFS for Linux

How to edit GRUB Settings with GUI tool QGRUBEditor

There is a tiny little program called QGRUBEditor. It is a system GUI tool to view and edit the GRUB boot loader. It offers many features and it is the perfect solution for those who want to change the way GRUB works, without messing with GRUB's configuration files. This is an excellent tool for a new user.

From the article:

If you've been running Linux long enough to have upgraded your system more than once, you probably have several Linux kernels lurking around your system. If you discover that a certain application no longer works for you, you can go back to a previous kernel to try to run your program. GRUB, the boot loader found in most Linux distributions, lets you choose among operating systems and kernels installed on your box. Many people, however, fear that messing with GRUB may ruin their system, because of its many esoteric options, and configuration file text that often contains no help comments. QGRUBEditor can help you view and edit the GRUB boot loader from a graphical user interface.

QGRUBEditor - A visual GUI GRUB configuration editor
(Fig 01: QGRUBEditor in action [image credit official project home page] )

Download QGRUBEditor ~ A visual GUI GRUB configuration editor

Visit official project page to download QGRUBEditor (Found via Linux.com )

Download of the day: Netbsd 4.0 CD ISO Image

NetBSD 4.0 has been released. It is available for download now. . NetBSD is a free, secure, and highly portable Unix-like Open Source operating system available for many platforms, from 64-bit Opteron machines and desktop systems to handheld and embedded devices. Its clean design and advanced features make it excellent in both production and research environments, and it is user-supported with complete source. Many applications are easily available through pkgsrc, the NetBSD Packages Collection.

Major achievements in NetBSD 4.0 include support for version 3 of the Xen virtual machine monitor, Bluetooth, many new device drivers and embedded platforms based on ARM, PowerPC and MIPS CPUs. New network services include iSCSI target (server) code and an implementation of the Common Address Redundancy Protocol. Also, system security was further enhanced with restrictions of mprotect(2) to enforce W^X policies, the Kernel Authorization framework, and improvements of the Veriexec file integrity subsystem, which can be used to harden the system against trojan horses and virus attacks.

Download NetBSD ISO CD

=> Visit official site to grab NetBSD 4 ISO images [i386 - 242M]
=> Announcing NetBSD 4.0