mesa: Reference count shaders that are used by transform feedback objects

Graphics / Mesa 3D Graphics Library / Mesa - Gert Wollny [collabora.com] - 13 November 2018 09:57 EST

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

caa964b422 mesa: Reference count shaders that are used by transform feedback objects
src/mesa/main/transformfeedback.c | 3 +++
1 file changed, 3 insertions(+)

Upstream: cgit.freedesktop.org


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