From 7c518460303353084ebcfca99bc4b67ce33745a1 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 23 Jan 2017 14:52:45 +0000 Subject: [PATCH] drm/i915: Pevent copying uninitialised garbage into vma->ggtt_view Since tweaking i915_vma_compare() we allowed constructors to skip clearing the ggtt_view believing that we didn't access the unused members. That, as it turns out, was not entirely true. In particular, i915_gem_fault() uses ret = remap_io_mapping(area, area->vm_start + (vma->ggtt_view.partial.offset << PAGE_SHIFT), (ggtt->mappable_base + vma->node.start) >> PAGE_SHIFT, min_t(u64, vma->size, area->vm_end - area->vm_start), &ggtt->mappable); i.e. the ggtt_view.partial for both normal and partial views. If we allowed garbage into the normal vma->ggtt_view and then try userspace tried to mmap it, we could explode in an unobvious fashion. Fixes: 7b92c047bae2 ("drm/i915: Eliminate superfluous i915_ggtt_view_rotated") Fixes: 3bf4d5751943 ("drm/i915: Stop clearing i915_ggtt_view") Reported-by: Matthew Auld Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Cc: Matthew Auld Link: http://patchwork.freedesktop.org/patch/msgid/20170123145245.3972-1-chris@chris-wilson.co.uk Tested-by: Matthew Auld Reviewed-by: Matthew Auld --- drivers/gpu/drm/i915/i915_vma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 307b22ae7791..155906e84812 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -91,7 +91,7 @@ vma_create(struct drm_i915_gem_object *obj, vma->size = obj->base.size; vma->display_alignment = I915_GTT_MIN_ALIGNMENT; - if (view) { + if (view && view->type != I915_GGTT_VIEW_NORMAL) { vma->ggtt_view = *view; if (view->type == I915_GGTT_VIEW_PARTIAL) { GEM_BUG_ON(range_overflows_t(u64, -- 2.20.1