Writing Device Drivers

Postmortem Debugging

Postmortem analysis offers numerous advantages to driver developers. More than one developer can examine a problem in parallel. Multiple instances of the debugger can be used simultaneously on a single crash dump. The analysis can be performed offline so that the crashed system can be returned to service, if possible. Postmortem analysis enables the use of user-developed debugger functionality in the form of dmods. Dmods can bundle functionality that would be too memory-intensive for real-time debuggers, such as kmdb.

When a system panics while kmdb is loaded, control is passed to the debugger for immediate investigation. If kmdb does not seem appropriate for analyzing the current problem, a good strategy is to use :c to continue execution and save the crash dump. When the system reboots, you can perform postmortem analysis with mdb on the saved crash dump. This process is analogous to debugging an application crash from a process core file.

Note –

In earlier versions of the Solaris operating system, adb(1) was the recommended tool for postmortem analysis. In the current Solaris operating system, mdb(1) is the recommended tool for postmortem analysis. The mdb() feature set surpasses the set of commands from the legacy crash(1M) utility. The crash utility is no longer available in the Solaris operating system.