diff --git a/kernel/dlmalloc/dlmalloc_port.inc b/kernel/dlmalloc/dlmalloc_port.inc
index 2e4613a..fe53949 100644
--- a/kernel/dlmalloc/dlmalloc_port.inc
+++ b/kernel/dlmalloc/dlmalloc_port.inc
@@ -68,6 +68,6 @@ void *sbrk(long inc) {
   uint64_t blocks = _DIV_ROUNDUP(inc, BITMAP_BLOCK_SIZE);
   uint8_t *virt = VIRT(pmm_alloc(blocks));
   hal_memset(virt, 0, blocks * BITMAP_BLOCK_SIZE);
-  _last = (void *)(virt + inc);
+  _last = (void *)(virt + (blocks * BITMAP_BLOCK_SIZE));
   return virt;
 }