master 41c3384: Fix double-free bug when finalizing module runtimes.

[Philipp Stephani]

branch: master
commit 41c338474dd1e086494337fd18ec8828cef1a75c
Author: Philipp Stephani <phst@google.com>
Commit: Philipp Stephani <phst@google.com>

    Fix double-free bug when finalizing module runtimes.
    
    * src/emacs-module.c (finalize_runtime_unwind): Don't finalize initial
    environment twice.
    
    * test/src/emacs-module-resources/mod-test.c (emacs_module_init):
    Allocate lots of values during module initialization to trigger the
    bug.
---
 src/emacs-module.c                         | 4 ++--
 test/src/emacs-module-resources/mod-test.c | 6 ++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/emacs-module.c b/src/emacs-module.c
index 5f97815..0f3ef59 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -1506,8 +1506,8 @@ finalize_environment_unwind (void *env)
 void
 finalize_runtime_unwind (void *raw_ert)
 {
-  struct emacs_runtime *ert = raw_ert;
-  finalize_environment (ert->private_members->env);
+  /* No further cleanup is required, as the initial environment is
+     unwound separately.  See the logic in Fmodule_load.  */
 }
 
 
diff --git a/test/src/emacs-module-resources/mod-test.c 
b/test/src/emacs-module-resources/mod-test.c
index 4196212..f855e9b 100644
--- a/test/src/emacs-module-resources/mod-test.c
+++ b/test/src/emacs-module-resources/mod-test.c
@@ -806,6 +806,12 @@ emacs_module_init (struct emacs_runtime *ert)
                                            strlen (interactive_spec)));
   bind_function (env, "mod-test-identity", identity_fn);
 
+  /* We allocate lots of values to trigger bugs in the frame allocator during
+     initialization.  */
+  int count = 10000;  /* larger than value_frame_size in emacs-module.c */
+  for (int i = 0; i < count; ++i)
+    env->make_integer (env, i);
+
   provide (env, "mod-test");
   return 0;
 }