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-rw-r--r--src/mesa/drivers/dri/i965/brw_draw_upload.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_draw_upload.c b/src/mesa/drivers/dri/i965/brw_draw_upload.c
index e7a87b6e09f..05079c043af 100644
--- a/src/mesa/drivers/dri/i965/brw_draw_upload.c
+++ b/src/mesa/drivers/dri/i965/brw_draw_upload.c
@@ -396,6 +396,20 @@ static void brw_prepare_vertices(struct brw_context *brw)
dri_bo_reference(input->bo);
input->offset = (unsigned long)input->glarray->Ptr;
input->stride = input->glarray->StrideB;
+
+ /* This is a common place to reach if the user mistakenly supplies
+ * a pointer in place of a VBO offset. If we just let it go through,
+ * we may end up dereferencing a pointer beyond the bounds of the
+ * GTT. We would hope that the VBO's max_index would save us, but
+ * Mesa appears to hand us min/max values not clipped to the
+ * array object's _MaxElement, and _MaxElement frequently appears
+ * to be wrong anyway.
+ *
+ * The VBO spec allows application termination in this case, and it's
+ * probably a service to the poor programmer to do so rather than
+ * trying to just not render.
+ */
+ assert(input->offset < input->bo->size);
} else {
if (input->bo != NULL) {
/* Already-uploaded vertex data is present from a previous