[PATCH] Fix memory leak on init/fini dependency list

[Andreas Schwab <schwab at redhat dot com>]

valgrind reports a memory leak when a program dlopens a library already
loaded as a direct dependency.  In this case the l_initfini memory
allocated in _dl_map_object_deps is not freed because dlclose won't
unload the library.  On the other hand we must not free the memory
allocated by the dummy malloc, so keep a flag whether the initfini
memory was allocated during startup.

Andreas.

2010-09-22  Andreas Schwab  <schwab@redhat.com>

	* include/link.h (struct link_map): Add l_free_initfini.
	* elf/dl-deps.c (_dl_map_object_deps): Set it when assigning
	l_initfini.
	* elf/rtld.c (dl_main): Clear it on all objects loaded on startup.
	* elf/dl-libc.c (free_mem): Free l_initfini if l_free_initfini is
	set.
---
 elf/dl-deps.c  |    2 ++
 elf/dl-libc.c  |    6 +++++-
 elf/rtld.c     |    1 +
 include/link.h |    3 +++
 4 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/elf/dl-deps.c b/elf/dl-deps.c
index a58de5c..e5b9cdf 100644
--- a/elf/dl-deps.c
+++ b/elf/dl-deps.c
@@ -478,6 +478,7 @@ _dl_map_object_deps (struct link_map *map,
 		  nneeded * sizeof needed[0]);
 	  atomic_write_barrier ();
 	  l->l_initfini = l_initfini;
+	  l->l_free_initfini = 1;
 	}
 
       /* If we have no auxiliary objects just go on to the next map.  */
@@ -662,6 +663,7 @@ Filters not supported with LD_TRACE_PRELINKING"));
   l_initfini[nlist] = NULL;
   atomic_write_barrier ();
   map->l_initfini = l_initfini;
+  map->l_free_initfini = 1;
   if (l_reldeps != NULL)
     {
       atomic_write_barrier ();
diff --git a/elf/dl-libc.c b/elf/dl-libc.c
index 7be9483..a13fce3 100644
--- a/elf/dl-libc.c
+++ b/elf/dl-libc.c
@@ -265,13 +265,13 @@ libc_freeres_fn (free_mem)
 
   for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns)
     {
-      /* Remove all additional names added to the objects.  */
       for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
 	{
 	  struct libname_list *lnp = l->l_libname->next;
 
 	  l->l_libname->next = NULL;
 
+	  /* Remove all additional names added to the objects.  */
 	  while (lnp != NULL)
 	    {
 	      struct libname_list *old = lnp;
@@ -279,6 +279,10 @@ libc_freeres_fn (free_mem)
 	      if (! old->dont_free)
 		free (old);
 	    }
+
+	  /* Free the initfini dependency list.  */
+	  if (l->l_free_initfini)
+	    free (l->l_initfini);
 	}
 
       if (__builtin_expect (GL(dl_ns)[ns]._ns_global_scope_alloc, 0) != 0
diff --git a/elf/rtld.c b/elf/rtld.c
index 2e266b1..9a560b3 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -2240,6 +2240,7 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
 	      lnp->dont_free = 1;
 	      lnp = lnp->next;
 	    }
+	  l->l_free_initfini = 0;
 
 	  if (l != &GL(dl_rtld_map))
 	    _dl_relocate_object (l, l->l_scope, GLRO(dl_lazy) ? RTLD_LAZY : 0,
diff --git a/include/link.h b/include/link.h
index 9d1fc1a..051b99a 100644
--- a/include/link.h
+++ b/include/link.h
@@ -192,6 +192,9 @@ struct link_map
 						 during LD_TRACE_PRELINKING=1
 						 contains any DT_SYMBOLIC
 						 libraries.  */
+    unsigned int l_free_initfini:1; /* Nonzero if l_initfini can be
+				       freed, ie. not allocated with
+				       the dummy malloc in ld.so.  */
 
     /* Collected information about own RPATH directories.  */
     struct r_search_path_struct l_rpath_dirs;
-- 
1.7.2.3


-- 
Andreas Schwab, schwab@redhat.com
GPG Key fingerprint = D4E8 DBE3 3813 BB5D FA84  5EC7 45C6 250E 6F00 984E
"And now for something completely different."