diff --git a/sys/kern/subr_diskmbr.c b/sys/kern/subr_diskmbr.c
index 34519b41ce2..9704ca74484 100644
--- a/sys/kern/subr_diskmbr.c
+++ b/sys/kern/subr_diskmbr.c
@@ -469,7 +469,7 @@ alpha_fix_srm_checksum(bp)
 	u_int64_t sum;
 	int i;
 
-	p = bp->b_data;
+	p = (u_int64_t *) bp->b_data;
 	sum = 0;
 	for (i = 0; i < 63; i++)
 		sum += p[i];