diff --git a/src/system/kernel/slab/allocator.cpp b/src/system/kernel/slab/allocator.cpp
index df55f095aa..4ba637501d 100644
--- a/src/system/kernel/slab/allocator.cpp
+++ b/src/system/kernel/slab/allocator.cpp
@@ -165,7 +165,7 @@ block_free(void* block, uint32 flags)
 void
 block_allocator_init_boot()
 {
-	for (int index = 0; index < kNumBlockSizes; index++) {
+	for (size_t index = 0; index < kNumBlockSizes; index++) {
 		char name[32];
 		snprintf(name, sizeof(name), "block allocator: %lu",
 			kBlockSizes[index]);