Gentoo † Cyberpunk 2077 path tracing crashes on AMD

Cyberpunk 2077's photo mode path tracing suddenly started crashing with a SIGSEGV on my RX 7900 XTX, even though it worked fine two days prior.

Setup: Gentoo, kernel 6.18.2, Mesa 25.3.2 (RADV), Proton.

The crash looked like this in the journal:

Process 58847 (GameThread) of user 1000 terminated abnormally with signal 11/SEGV

No GPU hang in dmesg, no amdgpu reset, just a straight segfault in the game thread.

I went through the usual suspects:

• Mesa had updated from 25.3.1 to 25.3.2 a few days earlier, but I had a screenshot with path tracing working after the update, so that wasn't it.
• No relevant package changes since then.
• Kernel hadn't changed.
• Full game reinstall didn't fix it.
• Switching proton versions (Proton GE, CachyOS, Proton Experimental) did not help either.

The fix turned out to be clearing the Mesa shader cache:

rm -rf $HOME/games/steam/steamapps/shadercache/1091500/
rm -rf $HOME/games/steam/steamapps/compatdata/1091500/pfx/drive_c/users/steamuser/AppData/Local/cache/
rm -rf ~/.cache/mesa_shader_cache/

The cache had grown quite large and likely contained stale or corrupted shaders from the last Mesa upgrade. The game and Steam shader cache directories were already clean, but Mesa's own cache sits outside of those and doesn't get touched by a game reinstall or Steam's "verify integrity".

Worth noting: Cyberpunk's path tracing on AMD Radeon GPUs seems to be fragile due to SHaRC (Spatially Hashed Radiance Cache). If clearing the shader cache doesn't help, disabling SHaRC via Advanced Path Tracing (a CET mod) could help too.

TL;DR: Try deleting ~/.cache/mesa_shader_cache/.

23:48 09.03.2026