mayocream/koharu

App crashes instantly on startup with AMD RDNA 4 (RX 9070) + ROCm 7.1 due to ZLUDA crash

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#754 opened on Jun 4, 2026

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Description

Describe the bug

Koharu crashes instantly (closes immediately without showing the GUI or logging Rust panics) when launched on a system with the new AMD RX 9070 (RDNA 4) and HIP SDK 7.1.

The issue is caused by the bundled ZLUDA version attempting to initialize the CUDA context on an unsupported driver (ROCm 7.1), resulting in a fatal Access Violation (0xc0000005) deep inside the AMD/ZLUDA JIT compiler.

Workaround Found

Since the crash happens before Rust can catch it (Hard Crash in C/C++ libraries), the app just dies. I had to manually compile a custom build of Koharu setting false in zluda.rs package_enabled function and enabling CPU multithreading (RAYON_NUM_THREADS="16") to make the app usable.

Feature Request

Please implement a hardware/driver check before blindly injecting ZLUDA. If hipInfo detects an RDNA 4 card (gfx12xx) or ROCm 7+, Koharu should automatically fallback to the CPU backend instead of attempting to load ZLUDA and crashing the entire application.

Bonus

Reported issue to ZLUDA https://github.com/vosen/ZLUDA/issues/646

Environment

  • OS: Windows 11
  • Koharu Version: 0.59.2
  • GPU: AMD Radeon RX 9070 16GB

Contributor guide

Research direction
Examine the ZLUDA initialization code, likely in `zluda.rs`, and modify the `package enabled` function to detect RDNA 4 or ROCm 7+ using `hipInfo` and disable ZLUDA, falling back to CPU backend.
Tech stack
rust
Domain
desktop
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitRust
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65