Pyxis GDB Auto-Load Plugin for DDT Container Debugging

This directory contains a GDB Python auto-load script that enables Linaro DDT (Forge) to fully resolve shared library symbols when debugging applications inside Pyxis containers.

How it works

When DDT’s GDB loads the target process’s dynamic linker (ld-linux), GDB’s auto-load mechanism loads this script. The script:

Reads /proc/<pid>/environ from the target process
Finds FORGE_SET_SYSROOT (set by Pyxis via spank_setenv)
Sets GDB’s sysroot to /proc/<pid>/root (direct container FS access)
Re-resolves all shared libraries from the container

This gives DDT full stack traces with symbols for all container libraries — not just the dynamic linker.

Installation layout

The RPM installs the canonical script and creates architecture-specific symlinks that GDB’s auto-load mechanism requires:

<prefix>/share/gdb/auto-load/
├── pyxis-sysroot.py                              (canonical source)
└── usr/
    ├── lib/
    │   ├── ld-linux-aarch64.so.1-gdb.py → ../../pyxis-sysroot.py
    │   └── ld-linux-x86-64.so.2-gdb.py → ../../pyxis-sysroot.py
    └── lib64/
        ├── ld-linux-aarch64.so.1-gdb.py → ../../pyxis-sysroot.py
        └── ld-linux-x86-64.so.2-gdb.py → ../../pyxis-sysroot.py

Activation

Set two environment variables before launching DDT:

export FORGE_ENABLE_CUSTOM_AUTOLOAD_DIR=/path/to/tools/pyxis-gdb-plugin
export FORGE_SET_SYSROOT="/"

Point this at the directory containing share/gdb/auto-load/. For SuPS: /opt/cray/sups/source/<version>/tools/pyxis-gdb-plugin.

For site-wide deployment, add these to the DDT/Forge modulefile.

Debug logging

Set PYXIS_GDB_PLUGIN_DEBUG=1 to write diagnostics to /tmp/pyxis-gdb-plugin.log.

Requirements

GDB 14+ with Python support (DDT 25.1.3 ships GDB 16.1)
DDT’s FORGE_ENABLE_CUSTOM_AUTOLOAD_DIR env var (supported in Forge 25.1+)

Full documentation

See Debugging with Linaro or TotalView for the complete user workflow.