The next sections describe in detail how kernel debugging is implementedĪs described in the README of ,

introspect kernel structures by parsing the kernel header and reading.

Virtual addresses, by patching the code with INT3Īnd then waiting for type-3 interrupts to occur

With these capabilities, it also becomes possible to: The debugging stub internal to the kernel generally has the tasks of: Machine, which sends commands to the kernel and displays the results. Very difficult, especially without knowing exactly which code has beenĮxecuted or the state of registers and memory similarly, the analysisĮxploits of security vulnerabilities requires an accurate study of theįor these reasons, operating systems often implement a kernelĬomposed of a simple agent running inside the kernel, which receives andĮxecutes debugging commands, and a complete debugger running on a remote Sources are available, tracing the root causes of such bugs is often ThisĬomplexity facilitates the introduction of likewise complex programmingĮrrors, which at minimum can cause the machine to stop or Of threads manipulating thousands of critical data structures. Of code, through which the kernel orchestrates the execution of hundreds Modern operating systems like macOS or iOS consist of millions of lines Mechanisms like ptrace or exception ports īut when working at kernel/driver/OS level, more powerful capabilities To examine running applications, operating systems provide Program freezes or crashes, and sometimes even security vulnerabilities.

I don't manage to crash the application.Debugging is the process of searching and correcting software issues If I remove the USB cable (terminate connection to microprocessor), (I thought that might crash the crashed process), I start seeing ~50% available CPU being used (not sure on what), and everything locks up. Nothing kills either cgdb or the process running in it. I'm not sure if something gets locked and never unlocked, but cgdb never exits. I'm fairly sure this is because if I kill from halfway through the application, I never release the /dev/ttyUSB device that I'm accessing the microcontroller through. cgdb refuses to ever kill the process - just sits there.

Find a bug, or try to exit the still running process using kill inside cgdb.

Set some breakpoints, etc, do some debugging.

I'm debugging using cgdb on Mac OS X 10.7.3. I've got a C++ application which connects over a USB serial link to a microprocessor, (similar to an Arduino).

Mac os debugger interrupt code