diff mbox

drm/i915: Use unsigned for overflow checks in execbuf

Message ID 1379592011-14751-1-git-send-email-daniel.vetter@ffwll.ch (mailing list archive)
State New, archived
Headers show

Commit Message

Daniel Vetter Sept. 19, 2013, noon UTC
There's actually no real risk since we already check for stricter
constraints earlier (using UINT_MAX / sizeof (struct
drm_i915_gem_exec_object2) as the limit). But in eb_create we use
signed integers, which steals a factor of 2. Luckily struct
drm_i915_gem_exec_object2 for this to not matter.

Still, be consistent and use unsigned integers.

Similar use unsinged integers when checking for overflows in the
relocation entry processing.

I've also added a new subtests to igt/gem_reloc_overflow to also
test for overflowing args->buffer_count values.

v2: Give the variables again tighter scope to make it clear that the
computation is purely local and doesn't leak out to the 2nd block.
Requested by Chris Wilson.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index a733118..742b127 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -48,15 +48,15 @@  eb_create(struct drm_i915_gem_execbuffer2 *args, struct i915_address_space *vm)
 	struct eb_vmas *eb = NULL;
 
 	if (args->flags & I915_EXEC_HANDLE_LUT) {
-		int size = args->buffer_count;
+		unsigned size = args->buffer_count;
 		size *= sizeof(struct i915_vma *);
 		size += sizeof(struct eb_vmas);
 		eb = kmalloc(size, GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
 	}
 
 	if (eb == NULL) {
-		int size = args->buffer_count;
-		int count = PAGE_SIZE / sizeof(struct hlist_head) / 2;
+		unsigned size = args->buffer_count;
+		unsigned count = PAGE_SIZE / sizeof(struct hlist_head) / 2;
 		BUILD_BUG_ON_NOT_POWER_OF_2(PAGE_SIZE / sizeof(struct hlist_head));
 		while (count > 2*size)
 			count >>= 1;
@@ -667,7 +667,7 @@  i915_gem_execbuffer_relocate_slow(struct drm_device *dev,
 	bool need_relocs;
 	int *reloc_offset;
 	int i, total, ret;
-	int count = args->buffer_count;
+	unsigned count = args->buffer_count;
 
 	if (WARN_ON(list_empty(&eb->vmas)))
 		return 0;
@@ -818,8 +818,8 @@  validate_exec_list(struct drm_i915_gem_exec_object2 *exec,
 		   int count)
 {
 	int i;
-	int relocs_total = 0;
-	int relocs_max = INT_MAX / sizeof(struct drm_i915_gem_relocation_entry);
+	unsigned relocs_total = 0;
+	unsigned relocs_max = UINT_MAX / sizeof(struct drm_i915_gem_relocation_entry);
 
 	for (i = 0; i < count; i++) {
 		char __user *ptr = to_user_ptr(exec[i].relocs_ptr);