[Mesa-dev] Google Earth + glReleaseShaderCompiler problem

[Brian Paul]

On 02/11/2013 07:19 PM, Eric Anholt wrote:
> Brian Paul<brianp at vmware.com>  writes:
>
>> Google Earth v7 calls glReleaseShaderCompiler() and Mesa's GLSL
>> compiler is crashing.
>>
>> In particular, it looks like glReleaseShaderCompiler() is getting
>> called between glCompileShader() and glLinkProgram().  The
>> glLinkProgram() call crashes when we try to reference some data
>> structures which were freed by glReleaseShaderCompiler().
>>
>> Here's an example from valgrind:
>>
>> ==10049== Invalid read of size 4
>> ==10049==    at 0x14FE4B9C: ir_call::ir_call(ir_function_signature*,
>> ir_dereference_variable*, exec_list*) (ir.h:1135)
>> ==10049==    by 0x14FEC269: ir_call::clone(void*, hash_table*) const
>> (ir_clone.cpp:181)
>> ==10049==    by 0x14FEC97A: ir_function_signature::clone(void*,
>> hash_table*) const (ir_clone.cpp:313)
>> ==10049==    by 0x14FEC8A3: ir_function::clone(void*, hash_table*)
>> const (ir_clone.cpp:290)
>> ==10049==    by 0x14FECDDA: clone_ir_list(void*, exec_list*, exec_list
>> const*) (ir_clone.cpp:433)
>> ==10049==    by 0x14F0750C: link_intrastage_shaders(void*,
>> gl_context*, gl_shader_program*, gl_shader**, unsigned int)
>> (linker.cpp:1062)
>> ==10049==    by 0x14F09B5E: link_shaders(gl_context*,
>> gl_shader_program*) (linker.cpp:2471)
>> ==10049==    by 0x1500064C: _mesa_glsl_link_shader (ir_to_mesa.cpp:3155)
>> ==10049==    by 0x14F96F36: link_program (shaderapi.c:758)
>> ==10049==    by 0x14F98165: _mesa_LinkProgram (shaderapi.c:1254)
>> ==10049==    by 0x8927796:
>> Gap::Gfx::GL2VertexShader::LinkPixelShader(unsigned int) (in
>> /opt/google/earth/free/libIGGfx.so)
>> ==10049==    by 0x893F9B2:
>> Gap::Gfx::GL2VertexShader::bind(Gap::Gfx::igOglVisualContext*) (in
>> /opt/google/earth/free/libIGGfx.so)
>> ==10049==  Address 0x8fd6cf0 is 40 bytes inside a block of size 80 free'd
>> ==10049==    at 0x402768C: free (in
>> /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
>> ==10049==    by 0x14EFB640: unsafe_free (ralloc.c:245)
>> ==10049==    by 0x14EFB610: unsafe_free (ralloc.c:238)
>> ==10049==    by 0x14EFB610: unsafe_free (ralloc.c:238)
>> ==10049==    by 0x14EFB55B: ralloc_free (ralloc.c:208)
>> ==10049==    by 0x14F02BB3: _mesa_glsl_release_functions()
>> (builtin_function.cpp:14643)
>> ==10049==    by 0x14EE7D95: _mesa_destroy_shader_compiler_caches
>> (glsl_parser_extras.cpp:1101)
>> ==10049==    by 0x14F987CC: _mesa_ReleaseShaderCompiler (shaderapi.c:1491)
>> ==10049==    by 0x891206C:
>> Gap::Gfx::GL2Shader::CompileShader(Gap::Gfx::igOglVisualContext*,
>> unsigned int, char const*) (in /opt/google/earth/free/libIGGfx.so)
>> ==10049==    by 0x89470A5:
>> Gap::Gfx::GL2VertexShader::CreateVertexShader(Gap::Gfx::igOglVisualContext*,
>> char const*, Gap::Gfx::igVertexDataList const*,
>> Gap::Gfx::igGfxShaderConstantList const*) (in
>> /opt/google/earth/free/libIGGfx.so)
>> ==10049==    by 0x894EC64:
>> Gap::Gfx::igOglVisualContext::createVertexShader_GL2(char const*,
>> Gap::Gfx::igVertexDataList const*, Gap::Gfx::igGfxShaderConstantList
>> const*) (in /opt/google/earth/free/libIGGfx.so)
>> ==10049==    by 0x8916479:
>> Gap::Gfx::igOglVisualContext::createVertexShader_OGL(char const*,
>> Gap::Gfx::IG_GFX_SHADER_LANGUAGE, Gap::Gfx::igVertexDataList const*,
>> Gap::Gfx::igGfxShaderConstantList const*, char const*, char const*,
>> Gap::Gfx::igGfxShaderDefineList const*) (in
>> /opt/google/earth/free/libIGGfx.so)
>> ==10049==
>>
>>
>> I've hacked several other Mesa GLSL tests to call
>> glReleaseShaderCompiler() between compile and link and get similar
>> results.
>>
>> Can someone look into fixing this?
>
> I just noticed this mail still marked todo, and I don't see a fix having
> landed.  I wrote up a piglit test that failed to reproduce this.  Can
> you write one?

I did. :)

I tried to repro this with some simple shaders, but it appears that 
larger shaders or particular shader features are needed.

I found that this patch to mesa mandelbrot demo reproduces the problem:

diff --git a/src/glsl/mandelbrot.c b/src/glsl/mandelbrot.c
index 31ede1d..7f19e9d 100644
--- a/src/glsl/mandelbrot.c
+++ b/src/glsl/mandelbrot.c
@@ -155,6 +155,7 @@ Init(void)

     vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
     fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
+   glReleaseShaderCompiler();
     program = LinkShaders(vertShader, fragShader);

     glUseProgram(program);


-Brian