Update list_entry() macro, which is basically the same as the
container_of() macro in the kernel, to use offsetof() to fix undefined
behavior.
Caught using clang -fsanitize=undefined.
Signed-off-by: Sami Liedes <sami.liedes@xxxxxx>
---
lib/blkid/list.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/lib/blkid/list.h b/lib/blkid/list.h
index c1cbfec..d15228e 100644
--- a/lib/blkid/list.h
+++ b/lib/blkid/list.h
@@ -148,8 +148,9 @@ _INLINE_ void list_splice(struct list_head *list, struct list_head *head)
* @type: the type of the struct this is embedded in.
* @member: the name of the list_struct within the struct.
*/
-#define list_entry(ptr, type, member) \
- ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
+#define list_entry(ptr, type, member) ({ \
+ const typeof( ((type *)0)->member ) *__mptr = (ptr); \
+ (type *)( (char *)__mptr - offsetof(type,member) );})
/**
* list_for_each - iterate over elements in a list
--
1.7.10.4
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