From: Gert Wollny <gert.wol...@collabora.com> Transform feedback objects may hold a pointer to a shader program, and at least in Gallium, this must be a valid pointer until ctx->Driver.EndTransformFeedback in glEndTransformFeedback has been called - which is conform with the spec that any program that is part of a current rendering state should only be flagged for deletion by glDeleteProgram. This was not handled properly for the transform feedback objects so that a call sequence
glUseProgram(x) glBeginTransformFreedback(...) glPauseTransformFeedback(...) glDeleteProgram(x) glEndTransformFeedback(...) would result in a use after free bug. With this patch the transform feedback object also updates the reference count to the used program thereby keeping the program valid as long as the transform feedback objects links to it. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108713 Fixes: 654587696b4234d09a6b471b70e9629cf2887c27 mesa: add end_transform_feedback() helper Signed-off-by: Gert Wollny <gert.wol...@collabora.com> --- I think the problem is longer in the code then the fixes commit, but this commit added the functions I'm patching. Thanks for any review, Gert src/mesa/main/transformfeedback.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/mesa/main/transformfeedback.c b/src/mesa/main/transformfeedback.c index a46c9f94bc..dd921aa5f9 100644 --- a/src/mesa/main/transformfeedback.c +++ b/src/mesa/main/transformfeedback.c @@ -40,6 +40,7 @@ #include "shaderapi.h" #include "shaderobj.h" +#include "program/program.h" #include "program/prog_parameter.h" struct using_program_tuple @@ -470,6 +471,7 @@ begin_transform_feedback(struct gl_context *ctx, GLenum mode, bool no_error) if (obj->program != source) { ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedbackProg; + _mesa_reference_program_(ctx, &obj->program, source); obj->program = source; } @@ -498,12 +500,14 @@ static void end_transform_feedback(struct gl_context *ctx, struct gl_transform_feedback_object *obj) { + FLUSH_VERTICES(ctx, 0); ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback; assert(ctx->Driver.EndTransformFeedback); ctx->Driver.EndTransformFeedback(ctx, obj); + _mesa_reference_program_(ctx, &obj->program, NULL); ctx->TransformFeedback.CurrentObject->Active = GL_FALSE; ctx->TransformFeedback.CurrentObject->Paused = GL_FALSE; ctx->TransformFeedback.CurrentObject->EndedAnytime = GL_TRUE; -- 2.18.1 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
