diff --git a/core/os/os.odin b/core/os/os.odin
index 971abd911..b71ea261e 100644
--- a/core/os/os.odin
+++ b/core/os/os.odin
@@ -194,7 +194,7 @@ heap_allocator_proc :: proc(allocator_data: rawptr, mode: mem.Allocator_Mode,
 		ptr := uintptr(aligned_mem)
 		aligned_ptr := (ptr - 1 + uintptr(a)) & -uintptr(a)
 		diff := int(aligned_ptr - ptr)
-		if (size + diff) > space {
+		if (size + diff) > space || allocated_mem == nil {
 			return nil, .Out_Of_Memory
 		}
 
diff --git a/core/os/os2/heap_linux.odin b/core/os/os2/heap_linux.odin
index b631268a1..136c3e6cb 100644
--- a/core/os/os2/heap_linux.odin
+++ b/core/os/os2/heap_linux.odin
@@ -166,7 +166,7 @@ _heap_allocator_proc :: proc(allocator_data: rawptr, mode: mem.Allocator_Mode,
 		ptr := uintptr(aligned_mem)
 		aligned_ptr := (ptr - 1 + uintptr(a)) & -uintptr(a)
 		diff := int(aligned_ptr - ptr)
-		if (size + diff) > space {
+		if (size + diff) > space || allocated_mem == nil {
 			return nil, .Out_Of_Memory
 		}
 
diff --git a/core/os/os2/heap_windows.odin b/core/os/os2/heap_windows.odin
index 0f154cd8c..eba403c1d 100644
--- a/core/os/os2/heap_windows.odin
+++ b/core/os/os2/heap_windows.odin
@@ -52,7 +52,7 @@ _heap_allocator_proc :: proc(allocator_data: rawptr, mode: mem.Allocator_Mode,
 		ptr := uintptr(aligned_mem)
 		aligned_ptr := (ptr - 1 + uintptr(a)) & -uintptr(a)
 		diff := int(aligned_ptr - ptr)
-		if (size + diff) > space {
+		if (size + diff) > space || allocated_mem == nil {
 			return nil, .Out_Of_Memory
 		}
 
diff --git a/core/runtime/os_specific_windows.odin b/core/runtime/os_specific_windows.odin
index 6e7474257..732715793 100644
--- a/core/runtime/os_specific_windows.odin
+++ b/core/runtime/os_specific_windows.odin
@@ -112,7 +112,7 @@ _windows_default_alloc_or_resize :: proc "contextless" (size, alignment: int, ol
 	ptr := uintptr(aligned_mem)
 	aligned_ptr := (ptr - 1 + uintptr(a)) & -uintptr(a)
 	diff := int(aligned_ptr - ptr)
-	if (size + diff) > space {
+	if (size + diff) > space || allocated_mem == nil {
 		return nil, .Out_Of_Memory
 	}