Stack Traces With gdb

Stack Traces With gdb   Okay, you've used top or ps to get the process ID, and strace hasn't told you anything useful. What next? The next step is to get a stack trace with gdb. A stack trace tells you not only what the program is actually doing right now at a low level (waiting on a network socket), but sometimes also higher level information (what sort of network read it was doing). Knowing how to use gdb to get stack traces is also handy if you ever need to file a bug...

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Kernel_flow

PreliminariesRefer to Net:Network Overview for an overview of all aspects of the networking kernel: routing, neighbour discovery, NAPI, filtering, ...The network data (including headers etc.) is managed through the sk_buff data structure. This minimizes copying overhead when going through the networking layers. A basic understanding of sk_buff is required to understand the networking kernel.The kernel as a whole makes heavy use of virtual methods. These are recorded as function pointers in data structures. In the figure these are indicated with diamonds. This article...

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Understanding locks in networking

Understanding locks in networking lock_sock and release_sock do not hold a normal spinlock directly but instead hold the owner field and do other housework as well.lock_sock grabs the lock sk->sk_lock.slock, disables local bottom halves and then it checks to see if there is an owner. If it does it spins until this releases, sets the owner and then releases sk->sk_lock.slock. This means bh_lock_sock can still execute even if the socket is "locked" provided of course that the lock_sock...

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From Noob to Ninja

 From Noob to Ninja Every Linux user has been new at some point, and unless you’ve got a history of UNIX administration, the transition was likely a bit daunting. Many people began learning Linux before sites like Google and StackExchange made it easy to find answers, and ended up having to figure everything out in their own. While inconvenient, this approach can force you to challenge yourself and learn things about the system that you might otherwise never find out. Usually here at...

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Pidgin SSL Certificate Error? Here’s The Fix

Pidgin SSL Certificate Error? Here’s The Fix Update: The latest version of Pidgin (2.7.7) has fixed this issue. For Windows users, uninstall your current version, download and install the latest version. For Ubuntu users, add the following PPA and update your system: sudo add-apt-repository ppa:pidgin-developers/ppa sudo apt-get update && sudo apt-get upgradeIf you are using Pidgin to connect to your MSN messenger, you will probably receive the SSL certificate error message. it’s...

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Install Photoshop CS5 in Ubuntu Maverick 10.10

Install Photoshop CS5 in Ubuntu Maverick 10.10 If you are running Ubuntu 10.10 Maverick and own a copy of the Photoshop CS 5 installer, you will find that you won’t be able to install it under wine. Photoshop CS5 on Ubuntu 10.4 works fine, but not 10.10. Here’s what I did to get it running on my Ubuntu Maverick machine. What you’ll need: A computer running Ubuntu Maverick A computer running Windows (it doesn’t have to be a computer. It can be a virtual machine running Windows in Virtualbox) A...

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Fix for GPG error UBUNTU

Fix for GPG error UBUNTU  When you try to access ubuntu extras you might see following GPG error W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://extras.ubuntu.com maverick Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192 W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/maverick/Release Solution Open the terminal...

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30 Black Hat SEO Techniques

30 Black Hat SEO Techniques  Wicked by xlorddashx. Black hat SEO is both a myth and a reality we have to face sooner or later as SEO practicioners. While I abide by probably one of the strictest SEO codes of ethics around and SEOptimise is a clean white hat SEO company company itself we still can’t deny that there is black hat SEO. The sheer existence of black hat SEO techniques must be acknowledged for several reasons.As Rishi Lakhani noted on his new SEO blog: You need it at least to...

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