1 files changed, 10 insertions, 2 deletions
diff --git a/rts/RtsUtils.h b/rts/RtsUtils.h
index f2b8bdd1d8..7f7e925cd4 100644
--- a/rts/RtsUtils.h
+++ b/rts/RtsUtils.h
@@ -22,10 +22,17 @@ void stgFree(void* p);
 void *stgMallocBytes(size_t n, char *msg)
     STG_MALLOC STG_MALLOC1(stgFree)
     STG_ALLOC_SIZE1(1);
+/* Note: unlike `stgReallocBytes` and `stgCallocBytes`, `stgMallocBytes` is
+ * *not* `STG_RETURNS_NONNULL`, since it will return `NULL` when the requested
+ * allocation size is zero.
+ *
+ * See: https://gitlab.haskell.org/ghc/ghc/-/issues/22380
+ */
 
 void *stgReallocBytes(void *p, size_t n, char *msg)
     STG_MALLOC1(stgFree)
-    STG_ALLOC_SIZE1(2);
+    STG_ALLOC_SIZE1(2)
+    STG_RETURNS_NONNULL;
 /* Note: `stgRallocBytes` can *not* be tagged as `STG_MALLOC`
  * since its return value *can* alias an existing pointer (i.e.,
  * the given pointer `p`).
@@ -35,7 +42,8 @@ void *stgReallocBytes(void *p, size_t n, char *msg)
 
 void *stgCallocBytes(size_t count, size_t size, char *msg)
     STG_MALLOC STG_MALLOC1(stgFree)
-    STG_ALLOC_SIZE2(1, 2);
+    STG_ALLOC_SIZE2(1, 2)
+    STG_RETURNS_NONNULL;
 
 char *stgStrndup(const char *s, size_t n);