Date: Mon, 17 Apr 2023 11:26:34 +0200
The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the macro “DECLARE_NEXT_HOLE_ADDR”.
Thus avoid the risk for undefined behaviour by moving the assignment
for the variable “node” behind the null pointer check.
This issue was detected by using the Coccinelle software.
Fixes: 5fad79fd66ff90b8c0a95319dad0b099008f8347 ("drm/mm: cleanup and improve next_hole_*_addr()")
Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_mm.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 8257f9d4f619..95c316aa36e5 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -389,9 +389,13 @@ first_hole(struct drm_mm *mm,
#define DECLARE_NEXT_HOLE_ADDR(name, first, last) \
static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \
{ \
- struct rb_node *parent, *node = &entry->rb_hole_addr; \
+ struct rb_node *parent, *node; \
\
- if (!entry || RB_EMPTY_NODE(node)) \
+ if (!entry) \
+ return NULL; \
+ \
+ node = &entry->rb_hole_addr; \
+ if (RB_EMPTY_NODE(node)) \
return NULL; \
\
if (usable_hole_addr(node->first, size)) { \
--
2.40.0
