gh-141770: Annotate anonymous mmap only for debug build

Author: corona10

Include/internal/pycore_pymem.h

@@ -11,6 +11,10 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
+#if defined(Py_DEBUG) && defined(HAVE_PR_SET_VMA_ANON_NAME)
+#include <sys/prctl.h>
+#endif
+
 // Try to get the allocators name set by _PyMem_SetupAllocators().
 // Return NULL if unknown.
 // Export for '_testinternalcapi' shared extension.
@@ -91,6 +95,16 @@ static inline int _PyMem_IsULongFreed(unsigned long value)
 #endif
 }
 
+static inline int _PyMem_Annotate_Mmap(void *addr, size_t size, const char *name)
+{
+#if defined(Py_DEBUG) && defined(HAVE_PR_SET_VMA_ANON_NAME)
+   prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, (unsigned long)addr, size, name);
+   return 0;
+#else
+   return 0;
+#endif
+}
+
 extern int _PyMem_GetAllocatorName(
     const char *name,
     PyMemAllocatorName *allocator);

configure

@@ -5578,6 +5578,12 @@ AC_CHECK_DECLS([UT_NAMESIZE],
               [],
               [@%:@include <utmp.h>])
 
+AC_CHECK_DECLS([PR_SET_VMA_ANON_NAME],
+              [AC_DEFINE([HAVE_PR_SET_VMA_ANON_NAME], [1],
+                         [Define if you have the 'PR_SET_VMA_ANON_NAME' constant.])],
+              [],
+              [@%:@include <linux/prctl.h>])
+
 # check for openpty, login_tty, and forkpty
 
 AC_CHECK_FUNCS([openpty], [],

configure.ac

@@ -228,6 +228,10 @@
 /* Define to 1 if you have the <db.h> header file. */
 #undef HAVE_DB_H
 
+/* Define to 1 if you have the declaration of 'PR_SET_VMA_ANON_NAME', and to 0
+   if you don't. */
+#undef HAVE_DECL_PR_SET_VMA_ANON_NAME
+
 /* Define to 1 if you have the declaration of 'RTLD_DEEPBIND', and to 0 if you
    don't. */
 #undef HAVE_DECL_RTLD_DEEPBIND
@@ -996,6 +1000,9 @@
 /* Define if your compiler supports function prototype */
 #undef HAVE_PROTOTYPES
 
+/* Define if you have the 'PR_SET_VMA_ANON_NAME' constant. */
+#undef HAVE_PR_SET_VMA_ANON_NAME
+
 /* Define to 1 if you have the 'pthread_condattr_setclock' function. */
 #undef HAVE_PTHREAD_CONDATTR_SETCLOCK