[PATCH] elf: Fix dlclose of an empty namespace in auditing mode (bug 26076)

[Florian Weimer]

ns->_ns_loaded is NULL if nothing has been loaded into the namespace.

It seems difficult to hit this bug reliably, so this change does not
come with a test case.  It was trigger by accident, due to TLS
exhaustion.

---
 elf/dl-close.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/elf/dl-close.c b/elf/dl-close.c
index 73b2817bbf..896e59e42e 100644
--- a/elf/dl-close.c
+++ b/elf/dl-close.c
@@ -782,7 +782,7 @@ _dl_close_worker (struct link_map *map, bool force)
     {
       struct link_map *head = ns->_ns_loaded;
       /* Do not call the functions for any auditing object.  */
-      if (head->l_auditing == 0)
+      if (head != NULL && head->l_auditing == 0)
 	{
 	  struct audit_ifaces *afct = GLRO(dl_audit);
 	  for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)