diff --git a/src/detection/swap/swap_obsd.c b/src/detection/swap/swap_obsd.c
index b64900c9f..414971d39 100644
--- a/src/detection/swap/swap_obsd.c
+++ b/src/detection/swap/swap_obsd.c
@@ -10,21 +10,24 @@ const char* ffDetectSwap(FFSwapResult* swap)
 {
     int nswap = swapctl(SWAP_NSWAP, 0, 0);
     if (nswap < 0) return "swapctl(SWAP_NSWAP) failed";
-    if (nswap == 0) NULL;
+    if (nswap == 0) return NULL;
 
-    struct swapent* swdev = malloc((uint32_t) nswap * sizeof(*swdev));
+    FF_AUTO_FREE struct swapent* swdev = malloc((uint32_t) nswap * sizeof(*swdev));
 
     if (swapctl(SWAP_STATS, swdev, nswap) < 0)
         return "swapctl(SWAP_STATS) failed";
 
+    uint64_t swapTotal = 0, swapUsed = 0;
     for (int i = 0; i < nswap; i++)
     {
         if (swdev[i].se_flags & SWF_ENABLE)
         {
-            swap->bytesUsed += (uint64_t) swdev[i].se_inuse * DEV_BSIZE;
-            swap->bytesTotal += (uint64_t) swdev[i].se_nblks * DEV_BSIZE;
+            swapUsed += (uint64_t) swdev[i].se_inuse;
+            swapTotal += (uint64_t) swdev[i].se_nblks;
         }
     }
+    swap->bytesUsed = swapUsed * DEV_BSIZE;
+    swap->bytesTotal = swapTotal * DEV_BSIZE;
 
     return NULL;
 }