Using Serial kdb / kgdb to Debug the Linux Kernel
summary
Serial kdb provides a text prompt on a device console and kgdb exposes a gdb server over a serial port; the demo boots a Chromebook, provokes crashes, uses dump_all and backtraces to capture all stacks, attaches a cross-compiled gdb via a KDMX PTY, and loads module symbols with LX scripts for module symbols so gdb shows C frames. Practical limits appear: kgdb can’t stop CPUs with interrupts disabled and optimized-out variables often require frame-walking or address-offset tricks.
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chapters (11)
- 0:00Start
- 2:34Syllabus
- 7:37What is kgdb good at?
- 12:33Getting setup - need a serial port
- 13:41Getting setup - kdmx
- 17:20Getting setup - kernel config
- 20:11Dropping into the debugger
- 23:34Debugging your first problem
- 29:16Demo: kgdb attaching
- 52:34Demo: Debugging a 2nd crash (1)
- 54:03Demo: Debugging a 2nd crash (2)
