sanity: Don't mark memory uninit in sanitize_{alloc,free}()

We might want to change the size of an allocated region without changing
which bytes are initialized.

2 files changed, 11 insertions, 9 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 79e4ce7..ef9f6ab 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -228,6 +228,7 @@ void arena_free(struct arena *arena, void *ptr) {
 	union chunk *chunk = ptr;
 	chunk_set_next(arena, chunk, arena->chunks);
 	arena->chunks = chunk;
+	sanitize_uninit(chunk, arena->size);
 	sanitize_free(chunk, arena->size);
 }
 
@@ -334,15 +335,16 @@ void *varena_realloc(struct varena *varena, void *ptr, size_t old_count, size_t
 	}
 
 	size_t old_size = old_arena->size;
-	sanitize_alloc((char *)ptr + old_exact_size, old_size - old_exact_size);
+	sanitize_alloc(ptr, old_size);
 
 	size_t new_size = new_arena->size;
 	size_t min_size = new_size < old_size ? new_size : old_size;
 	memcpy(ret, ptr, min_size);
 
 	arena_free(old_arena, ptr);
-	sanitize_free((char *)ret + new_exact_size, new_size - new_exact_size);
 
+	sanitize_free(ret, new_size);
+	sanitize_alloc(ret, new_exact_size);
 	return ret;
 }
 
diff --git a/src/sanity.h b/src/sanity.h
index 0b770cf..3f6020b 100644
--- a/src/sanity.h
+++ b/src/sanity.h
@@ -20,6 +20,11 @@
 #define SANITIZE_CALL__(macro, ptr, size, ...) \
 	macro(ptr, size)
 
+/**
+ * Squelch unused variable warnings when not sanitizing.
+ */
+#define sanitize_ignore(ptr, size) ((void)(ptr), (void)(size))
+
 #if __SANITIZE_ADDRESS__
 #  include <sanitizer/asan_interface.h>
 
@@ -38,8 +43,8 @@
 #define sanitize_free(...) SANITIZE_CALL(__asan_poison_memory_region, __VA_ARGS__)
 
 #else
-#  define sanitize_alloc sanitize_uninit
-#  define sanitize_free sanitize_uninit
+#  define sanitize_alloc(...) SANITIZE_CALL(sanitize_ignore, __VA_ARGS__)
+#  define sanitize_free(...) SANITIZE_CALL(sanitize_ignore, __VA_ARGS__)
 #endif
 
 #if __SANITIZE_MEMORY__
@@ -65,11 +70,6 @@
 #endif
 
 /**
- * Squelch unused variable warnings when not sanitizing.
- */
-#define sanitize_ignore(ptr, size) ((void)(ptr), (void)(size))
-
-/**
  * Initialize a variable, unless sanitizers would detect uninitialized uses.
  */
 #if __SANITIZE_MEMORY__