fix undefined behavior in free

diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
index d5ee4280e9324ead8464dfd7ad2f37eb21d950d1..9e05e1d6ade9bb75c52811cbbb0c0f95049fafa8 100644 (file)
--- a/src/malloc/malloc.c
+++ b/src/malloc/malloc.c
@@ -450,14 +450,15 @@ copy_realloc:
 
 void free(void *p)
 {
-       struct chunk *self = MEM_TO_CHUNK(p);
-       struct chunk *next;
+       struct chunk *self, *next;
        size_t final_size, new_size, size;
        int reclaim=0;
        int i;
 
        if (!p) return;
 
+       self = MEM_TO_CHUNK(p);
+
        if (IS_MMAPPED(self)) {
                size_t extra = self->psize;
                char *base = (char *)self - extra;