| Summary: | [GLSL compiler] SIGSEGV for shaders/glsl-fs-inline-explosion | ||
|---|---|---|---|
| Product: | Mesa | Reporter: | Kai <kai> |
| Component: | glsl-compiler | Assignee: | Ian Romanick <idr> |
| Status: | RESOLVED MOVED | QA Contact: | Intel 3D Bugs Mailing List <intel-3d-bugs> |
| Severity: | normal | ||
| Priority: | medium | CC: | huax.lu, mellery, mesa-dev |
| Version: | git | ||
| Hardware: | x86-64 (AMD64) | ||
| OS: | Linux (All) | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
| Attachments: |
Full GDB backtrace and register dump
Full GDB backtrace and register dump error-checking in glsl-compiler error-checking in glsl-compiler |
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Created attachment 89466 [details]
Full GDB backtrace and register dump
Still an issue with current Mesa HEAD (21ae5135dd30bbd2ec7d2b44e07b6cb1d6425d9e).
Adding mesa-dev, since I'm pretty sure others besides the fine people at Intel might have an idea what the cause is. ;-) The cause has been known since the tests were added in 2010: commit 656cc65b2d3782c078d36342d0deec9886514520 Author: Luca Barbieri <luca@luca-barbieri.com> Date: Mon Sep 6 04:56:05 2010 +0200 add GLSL inlining/unroll limit tests, currently failing The current GLSL compiler inlines everything indiscriminately, and unrolls all loops that have a small iteration count. This is a bad idea, because it can lead to exponential growth of the code, as these test cases illustrate. On a naive implementation (like current Mesa) these tests will attempt to allocate more than 2^64 bytes of RAM, ensuring failure. A smart implementation will instead generate actual calls/loops, and the test passes, since the branch protecting the functions/loops is not taken. Currently they aren't added to any profile since they obviously cause piglit to hang until memory is exhausted, possibly causing lots of swap thrashing. Not sure, whether this should be closed or not, but I don't see the test in todays Piglit run. And certainly not among the three crashed tests. Created attachment 106343 [details]
error-checking in glsl-compiler
What's going on here, seems to be that we're running out of memory while linking the shader (during optimizations, but that's probably just dumb luck). This makes ralloc_size return a NULL-pointer, which gets dereferenced because the only guards against NULL-pointers in the compiler seems to be asserts.
The attached patch fixes *that* issue for me, but it doesn't make the test pass, nor fail gracefully either; all that happens is that piglit itself runs out of memory, triggering an assert.
Besides, it doesn't seem like exceptions is exactly good style in this project. So I dunno...
Created attachment 106345 [details] [review] error-checking in glsl-compiler Adding a try-catch block around the lifespan around mem_ctx seems to have helped, now the test plain fails instead of crashing. *** Bug 84215 has been marked as a duplicate of this bug. *** -- GitLab Migration Automatic Message -- This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity. You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/mesa/mesa/issues/798. |
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Created attachment 88181 [details] Full GDB backtrace and register dump While running Piglit on radeonsi (full graphics stack detailed below) I encountered an crash in "shaders/glsl-fs-inline-explosion". See the attached GDB backtrace and register dump for more details. Stack: GPU: "PITCAIRN" (ChipID = 0x6819) Linux: 3.11.6 libdrm: 2.4.47 LLVM: SVN:trunk/r193475 libclc: Git:master/4c18120c1a Mesa: Git:master/64c081e8b7 GLAMOR: Git:master/ba209eeef2 DDX: Git:master/f1dc677e79 Let me know if you need further information.