From: Nitin Gote Date: Fri, 18 Jul 2025 10:50:51 +0000 (+0530) Subject: iosys-map: Fix undefined behavior in iosys_map_clear() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=5634c8cb298a7146b4e38873473e280b50e27a2c;p=users%2Fjedix%2Flinux-maple.git iosys-map: Fix undefined behavior in iosys_map_clear() 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 Reviewed-by: Andi Shyti Reviewed-by: Thomas Zimmermann Signed-off-by: Thomas Zimmermann Link: https://lore.kernel.org/r/20250718105051.2709487-1-nitin.r.gote@intel.com --- 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)); } /**