[TF2] Engine-side segfault crash in engine.so during regular play

[nevadaa]

Team Fortress 2 crashed with a segmentation fault during normal gameplay on Fedora KDE Linux.
The crash occurred inside engine.so, after a prolonged stable runtime, with no context switches (no alt-tab, no Steam overlay (shift+tab)).

The game ran normally for approximately ~30 minutes total (including ~20 minutes in menus) before crashing mid-combat.

A Breakpad minidump was generated and successfully uploaded to Valve’s crash reporting infrastructure.

Linux environment:

OS: Fedora KDE 43, on a custom kernel (6.18.2_tkg_bmq_llvm (64-bit))
Graphics platform/session: Wayland (XWayland in game)
Steam: Flatpak (com.valvesoftware.Steam)
Graphics API: Vulkan (not legacy OpenGL)
GPU: AMD Radeon RX 56 Vega
CPU: Ryzen 5 3600 6-Core
Fullscreen (no borderless or windowed)

Gameplay context:

Map: pl_frontier
Class (played all throughout the map session): Medic
Game state: Mid-combat during final point push
Action at crash: Immediately before healing a Sniper
Menus: First ~20 minutes were spent idle in menus before joining a match

Crash Details:

Signal: SIGSEGV (segmentation fault)
Faulting module: engine.so
Crash type: Engine-side invalid memory access
Thread: Main engine thread
Breakpad CrashID: bp-f0fbc153-5107-42af-abab-461622251227
additional Breakpad CrashIDs for two other repeated crashes:
bp-8170b593-7e7e-4611-82c2-55f8b2251227
bp-7ddc11f3-3cec-444a-9f59-b23be2251227

journalctl/Stack Trace log:

crash.log

[WafiWadud]

seems like the engine either leaked memory or read from out of bounds memory, buffer overflow or something like that in the later case

[WafiWadud]

Have you crashed any time after that? Maybe it is a memory/stack/heap related problem, and somewhere something overflowed or underflowed or read out of bounds. If it hasn't crashed much after that, I'd chalk it up to some rare bug and leave it be

[nevadaa]

Hey! No, I haven't crashed any times since then. The one thing I did change since this segfault crash was reduce my RAM's speed from 3200 MT/s to 3000 MT/s which seems to have allowed for increased game stability. No crashes since doing this.

[nevadaa]

Maybe I should close the issue in that case? I feel like this is still worth looking into though.

[WafiWadud]

Your ram speed might have affected it slightly, but the main fault is an out of bounds read or write:
Crash type: Engine-side invalid memory access

[WafiWadud]

Try to reproduce the crash with the same memory speed and without the same memory speed

[nevadaa]

It seems to be largely irreproducible. I've not had a crash since.