malloc_debug: iterate: use usable_size

malloc_iterate with malloc debug enabled was returning allocation sizes
using the requested size instead of usable size.  If anything wrote
pointers above the requested size but below the usable size, those
pointers would be invisible to libmemunreachable and referenced
allocations could be reported as a leak.

Bug: 27107100
Change-Id: I6b19fd631f68ce93b3aee408cc3d296ec457bd01
(cherry picked from commit b23c6606d2326f8835fc7fc35b23ff7ee5a48f48)

1 files changed, 1 insertions, 1 deletions

diff --git a/libc/malloc_debug/malloc_debug.cpp b/libc/malloc_debug/malloc_debug.cpp
index aa6f5f747..fdad5416c 100644
--- a/libc/malloc_debug/malloc_debug.cpp
+++ b/libc/malloc_debug/malloc_debug.cpp
@@ -594,7 +594,7 @@ int debug_iterate(uintptr_t base, size_t size,
             if (g_debug->track->Contains(header)) {
               // Return just the body of the allocation if we're sure the header exists
               ctx->callback(reinterpret_cast<uintptr_t>(g_debug->GetPointer(header)),
-                  header->real_size(), ctx->arg);
+                  header->usable_size, ctx->arg);
               return;
             }
           }