From: Sami Liedes Date: Mon, 17 Dec 2012 15:22:35 +0000 (+0100) Subject: include/list: fix undefined behavior in list_entry() macro X-Git-Tag: v2.23-rc1~423 X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=becd09500f4abe1c11edb42289f4f6b453b01c65;p=thirdparty%2Futil-linux.git include/list: fix undefined behavior in list_entry() macro 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. [kzak@redhat.com: port from e2fsprogs] Signed-off-by: Sami Liedes Signed-off-by: Karel Zak --- diff --git a/include/list.h b/include/list.h index 1824af05d2..414d356ba1 100644 --- a/include/list.h +++ b/include/list.h @@ -163,8 +163,9 @@ _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) );}) #define list_first_entry(head, type, member) \