Specifications

Red Hat Enterprise Linux to Oracle Solaris Porting Guide

Debugging Applications

Many powerful tools are available on Oracle Solaris 11 for debugging software. These debugging tools

can be broadly categorized as follows:

• Kernel-land debuggers, for running in kernel mode

− Kernel mode maps to the privilege mode of the CPU. Examples of kernel modules include file

system kernel modules, device drivers, and so on.

• User-land debuggers for running in user mode

− User-land maps to the non-privilege mode of the CPU. User-land is where applications execute

and the applications interface to the OS kernel via system calls. Kernel-land code and user-land

code have different address spaces.

• Tools for addressing specific issues

− This includes tools for detecting memory-access errors or leaks, code coverage, data races and

deadlocks, hot locks, and so on.

Kernel Debuggers

The tools under this category are used for debugging code running in kernel mode (which maps to the

privilege mode of the CPU). The most popular tools among kernel developers are kdb and mdb:

• kdb is the interactive kernel debugger.

• mdb is the modular debugger generally used for debugging the live kernel, processes, core dumps,

memory leaks, and so on, but it can also be used for debugging application core dumps. mdb is a

very popular tool for debugging system crash dumps. It is an easy-to-extend utility for low-level

debugging and it is modularized. Oracle Solaris 11 includes a set of mdb modules that assist

programmers in debugging the Oracle Solaris kernel and related device drivers. Third-party

developers can develop their own debugging modules for supervisor or user software.

Source-Level Debugging with dbx

Similar to gdb (the GNU debugger on Linux), dbx is a proprietary source-level debugger shipped

with Oracle Solaris Studio. dbx can be used for source-level debugging and execution of programs

written in C++, ANSI C, Fortran 77, Fortran 95, and Java programming languages. It provides

symbolic debugging for programs written in C and C++. Useful features of dbx include stepping

through programs one source line or one machine instruction at a time. In addition to simply viewing

the operation of the program, variables can be manipulated and a wide range of expressions can be

evaluated and displayed. A program, a running process, or a core file can be debugged using dbx.

When dbx is used to debug a running process, the process is stopped.

To use dbx effectively, you need a debug binary, that is, you need to build your source code with the -

g compiler flag. Also note that the full debugging information is available only with no compiler

optimization. Only partial debugging support is available for optimized code. dbx allows you to modify