Poison freed memory objects

When compiled w/ -DCLIB_DEBUG=1, paint 0x13 across freed memory
blocks. Should result in a characteristic SIGSEGV if someone
dereferences a pointer in a freed vector element, etc.

Change-Id: I5f78970f4342310bfbe7adeddb56feff21f0de2c
Signed-off-by: Dave Barach <dave@barachs.net>

diff --git a/src/vppinfra/dlmalloc.c b/src/vppinfra/dlmalloc.c
index 8ae92cf..1bc8f65 100644 (file)
--- a/src/vppinfra/dlmalloc.c
+++ b/src/vppinfra/dlmalloc.c
@@ -4271,6 +4271,14 @@ void mspace_put (mspace msp, void *p_arg)
       mheap_put_trace ((u64)p_arg, psize);
     }
 
+#if CLIB_DEBUG > 0
+  /* Poison the object */
+  {
+    size_t psize = mspace_usable_size (object_header);
+    memset (object_header, 0x13, psize);
+  }
+#endif
+
   /* And free it... */
   mspace_free (msp, object_header);
 }