Resolving Runtime Crashes and Adding Cross-Architecture Support in Magma

Project: Magma (A Linux Foundation mobile core network platform)
Pull Requests: #15813 · #15812
Tech Stack: C++, CMake, x86/ARM Architecture

The Problem: Silent Crashes in the Access Gateway

Magma's Access Gateway is the component responsible for routing traffic between radio networks and the mobile core. It is critical infrastructure — when it fails, it fails silently and severely.

During my LFX mentorship, I was tasked with triaging a series of critical runtime crashes affecting the Access Gateway. Unlike compile-time errors, runtime crashes are particularly difficult to diagnose: the code builds cleanly, tests pass, and then the program falls apart the moment it runs under real conditions.

The root cause turned out to be two compounding issues:

1. A C++ namespace collision — two symbols with identical names existed in the same scope without explicit disambiguation. The compiler was silently resolving to the wrong one, causing undefined behavior at runtime.
2. Incorrect linker paths — the linker was failing to locate the correct object files, preventing the executable from assembling correctly.

The Solution: Diagnosis, Disambiguation, and Documentation

I tackled this in layers.

First, I traced the crash through the call stack and identified the conflicting symbol. Fixing the namespace collision required adding explicit qualifications throughout the affected files — ensuring the compiler resolved every name to the correct definition.

Second, I corrected the linker paths in the build configuration, so that all object files could be located and assembled into a valid executable.

Finally, I extended the work further by adding cross-architecture support across x86 and ARM processors. The existing build configuration had implicit assumptions about the host architecture baked in. Making the codebase work correctly across both targets required auditing those assumptions and replacing them with architecture-aware configurations.

Key Changes:

• Identified and resolved a C++ namespace collision causing incorrect symbol resolution at runtime.
• Corrected linker paths in the build system to ensure proper object file resolution.
• Added cross-architecture support for x86 and ARM, validated against both targets.
• Documented the complete root cause analysis for the team knowledge base.

The Challenge: Testing Across Heterogeneous Infrastructure

The hardest part of this contribution wasn't the fix itself — it was validation.

Runtime crashes caused by namespace collisions don't always reproduce consistently. The behavior depends on which translation unit is compiled first, what optimizations the compiler applies, and what the runtime state looks like at the moment of the collision. I had to construct test cases that could reliably trigger the bad behavior, prove that the fix resolved it, and ensure it wouldn't regress.

Cross-architecture testing added another layer of complexity. x86 and ARM have different ABI conventions, memory alignment rules, and instruction sets. A fix that works cleanly on one architecture can still break silently on the other. I worked directly with senior maintainers to validate test cases across both targets and ensure full regression coverage across heterogeneous infrastructure.

The Outcome & Learnings

Both PRs were reviewed by senior maintainers and merged into Magma's main branch.

This contribution taught me that diagnosing a bug is often harder than fixing it. The actual code changes were targeted. The work that preceded them — reading crash logs, tracing symbol resolution, understanding the build system — took far longer. I also learned how important documentation is in a distributed open-source team. The root cause analysis I wrote wasn't just a post-mortem; it was a knowledge artifact that could prevent the same class of bug from recurring.

Working across architectures reinforced something I hadn't fully appreciated before: assumptions are the silent bugs of every codebase. The more invisible an assumption is, the harder it is to find when it breaks.