Make smalloc redzone pointer properly aligned

[fio.git] / smalloc.c

diff --git a/smalloc.c b/smalloc.c
index e82ef1da0b59faab23a706db1257808c3fb10bbb..e0bc49818e23c3aa1049662038b8562f0891d301 100644 (file)
--- a/smalloc.c
+++ b/smalloc.c
@@ -268,9 +268,20 @@ void scleanup(void)
 }
 
 #ifdef SMALLOC_REDZONE
+static void *postred_ptr(struct block_hdr *hdr)
+{
+       const int int_mask = sizeof(unsigned int) - 1;
+       unsigned long ptr;
+
+       ptr = (unsigned long) hdr + hdr->size - sizeof(unsigned int);
+       ptr = (ptr + int_mask) & ~int_mask;
+
+       return (void *) ptr;
+}
+
 static void fill_redzone(struct block_hdr *hdr)
 {
-       unsigned int *postred = (void *) hdr + hdr->size - sizeof(unsigned int);
+       unsigned int *postred = postred_ptr(hdr);
 
        hdr->prered = SMALLOC_PRE_RED;
        *postred = SMALLOC_POST_RED;
@@ -278,7 +289,7 @@ static void fill_redzone(struct block_hdr *hdr)
 
 static void sfree_check_redzone(struct block_hdr *hdr)
 {
-       unsigned int *postred = (void *) hdr + hdr->size - sizeof(unsigned int);
+       unsigned int *postred = postred_ptr(hdr);
 
        if (hdr->prered != SMALLOC_PRE_RED) {
                fprintf(stderr, "smalloc pre redzone destroyed!\n");
@@ -414,8 +425,12 @@ static void *smalloc_pool(struct pool *pool, unsigned int size)
        unsigned int alloc_size = size + sizeof(struct block_hdr);
        void *ptr;
 
+       /*
+        * Use twice the size for good luck, we may need to adjust
+        * alignment.
+        */
 #ifdef SMALLOC_REDZONE
-       alloc_size += sizeof(unsigned int);
+       alloc_size += 2 * sizeof(unsigned int);
 #endif
 
        ptr = __smalloc_pool(pool, alloc_size);