Created attachment 132362 [details] Code to reproduce the crash I get a segfault when calling glLinkProgram because of a memcpy with dst=0 at brw_program_cache.c:370: memcpy((char *)cache->bo->virtual + item->offset, data, data_size); I attached a sample to trigger this which needs -lgbm -lGL -lEGL. (My CPU is a Intel i5-3320M, which comes with HD Graphics 4000 according to wikipedia)
We talked about this on IRC today, and vsyrjala noticed that the example program fopens the rendernode with "w" mode - for writing, but not reading. The fix is to use "r+" (reading and writing). Apparently if you can't read from the rendernode device, then GTT mappings fail, which gives us a NULL pointer for the program cache map.
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