Bug 107204

Summary: GPU hang (ring gfx timeout) with out of bounds UBO read in shader
Product: Mesa Reporter: Miłosz Rachwał <fbz-me>
Component: Drivers/Gallium/radeonsiAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact: Default DRI bug account <dri-devel>
Severity: normal    
Priority: medium    
Version: git   
Hardware: All   
OS: All   
Whiteboard:
i915 platform: i915 features:
Attachments: Dumps from GALLIUM_DDEBUG

Description Miłosz Rachwał 2018-07-12 12:45:24 UTC 
Created attachment 140587 [details]
Dumps from GALLIUM_DDEBUG

It hangs in OpenGL game immediately after startup almost always (but sometimes it goes through and works) with dmesg message:
>[drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, last signaled seq=3324, last emitted seq=3327

I tested it on Radeon RX580, mainline kernel 4.18, Mesa 18.1.3 and Mesa git c0874947f1.

I could provide game code for testing but I would have to package minimal assets as full game weights pretty much.
Comment 1 Miłosz Rachwał 2018-07-13 16:28:43 UTC 
It turned out that the cause was uninitialized UBO, which depending on memory contents leaded to out of bounds UBO array read in fragment shader.
It probably shouldn't bring down whole GPU, though.
Comment 2 GitLab Migration User 2019-09-25 18:09:10 UTC 
-- GitLab Migration Automatic Message --

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