https://github.com/python1320/gmsv_segfault
Zero runtime cost segfault debugging module for Garry's Mod [old]
https://github.com/python1320/gmsv_segfault
binary-module debugging debugging-tool garrysmod
Last synced: 4 days ago
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Zero runtime cost segfault debugging module for Garry's Mod [old]
- Host: GitHub
- URL: https://github.com/python1320/gmsv_segfault
- Owner: Python1320
- License: apache-2.0
- Created: 2026-06-09T20:22:47.000Z (11 days ago)
- Default Branch: main
- Last Pushed: 2026-06-09T21:50:24.000Z (10 days ago)
- Last Synced: 2026-06-15T19:38:34.967Z (5 days ago)
- Topics: binary-module, debugging, debugging-tool, garrysmod
- Language: C++
- Homepage:
- Size: 33.2 KB
- Stars: 3
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# gmsv_segfault
> [!WARNING]
> HERE BE DRAGONS
*VERY EXPERIMENTAL (and old) Garry's Mod server binary module for crash signal handling and debugging.*
*Used on [Metastruct](https://metastruct.github.io) and partner servers for past ~10 years for the (very frequent) crash reason debugging.*
Catches fatal signals (SIGSEGV, SIGABRT, SIGBUS, SIGILL, SIGQUIT, SIGHUP, SIGUSR1, SIGUSR2) and dumps:
- Signal info and fault address
- CPU register state
- C++ backtrace via libunwind (with demangled symbols)
- Lua stack trace and stack contents
- Thread crash detection
**Example crash dump**: [example_crash.log](example_crash.log)
**Also includes:**
- physics crash mitigation (*requires additional cursed stuff*)
**Custom signals to send to SRCDS**
- **SIGUSR1**: Lua watchdog to break infinite loops
- **SIGUSR2**: to dump manually.
Crash log is written to `$PWD/logs/.log` with a symlink at `logs/latest.log`.
**Build**
1. [Install premake](https://premake.github.io/download/)
2. Install dependencies
```sh
apt-get install libunwind-dev binutils-dev liblzma-dev build-essential
```
2. Copy this repo inside the gbins alongside all the other binary modules (*or really just rewrite build, please*)
**Install**
1. Put `gmsv_segfault_linux.dll` into `garrysmod/lua/bin/` (there is a precompiled version in Releases).
2. install autorun lua to server.
### Notes
- Debug builds (`#define CRASH_DEBUG`) register:
| Lua function | C function | Description |
|---|---|---|
| `docrash` | `lua_dosegfault` | Triggers a SIGSEGV |
| `docrash_stack` | `lua_dostack` | Triggers a stack overflow |
| `docrash_nullptr` | `lua_docrash_nullptr` | Calls through a null pointer |
| `docrash_thread` | `lua_docrash_thread` | Crashes in a separate thread |
- Originally extracted from [gitlab.com/metastruct/internal/gbins](https://gitlab.com/metastruct/internal/gbins) (internal)
- Depends on [`gmsv_physframe_linux.dll`](https://github.com/Python1320/gmsv_physframe) for stopping physics in a way that (sometimes) prevents further crashing to allow the occasional countdown while players can save their dupes.
## Thanks
Garry, [Metastruct](https://metastruct.github.io), FreezeBug, BlueShank, MetaMan, SpiralP, CapsAdmin, etc, etc etc