The current iosys_map_clear() implementation reads the potentially
uninitialized 'is_iomem' boolean field to decide which union member
to clear. This causes undefined behavior when called on uninitialized
structures, as 'is_iomem' may contain garbage values like 0xFF.
UBSAN detects this as:
UBSAN: invalid-load in include/linux/iosys-map.h:267
load of value 255 is not a valid value for type '_Bool'
Fix by unconditionally clearing the entire structure with memset(),
eliminating the need to read uninitialized data and ensuring all
fields are set to known good values.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14639
Fixes: 01fd30da0474 ("dma-buf: Add struct dma-buf-map for storing struct
dma_buf.vaddr_ptr")
Signed-off-by: Nitin Gote <nitin.r.g...@intel.com>
---
include/linux/iosys-map.h | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/include/linux/iosys-map.h b/include/linux/iosys-map.h
index 4696abfd311c..3e85afe794c0 100644
--- a/include/linux/iosys-map.h
+++ b/include/linux/iosys-map.h
@@ -264,12 +264,7 @@ static inline bool iosys_map_is_set(const struct iosys_map
*map)
*/
static inline void iosys_map_clear(struct iosys_map *map)
{
- if (map->is_iomem) {
- map->vaddr_iomem = NULL;
- map->is_iomem = false;
- } else {
- map->vaddr = NULL;
- }
+ memset(map, 0, sizeof(*map));
}
/**
--
2.25.1
