Don't allow a mismatch between obj->base.size/vma->size and the actual
number of pages for the backing store, which is limited to INT_MAX
pages.
Signed-off-by: Matthew Auld <matthew.a...@intel.com>
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index e5558af111e2..fef96a303d9d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -768,6 +768,18 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
if (args->flags & ~(I915_USERPTR_READ_ONLY |
I915_USERPTR_UNSYNCHRONIZED))
return -EINVAL;
+ /*
+ * XXX: There is a prevalence of the assumption that we fit the
+ * object's page count inside a 32bit _signed_ variable. Let's document
+ * this and catch if we ever need to fix it. In the meantime, if you do
+ * spot such a local variable, please consider fixing!
+ */
+
+ if (args->user_size >> PAGE_SHIFT > INT_MAX)
+ return -E2BIG;
+
+ if (overflows_type(args->user_size, obj->base.size))
+ return -E2BIG;
if (!args->user_size)
return -EINVAL;
--
2.20.1
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