* elf/dl-close.c (_dl_close_worker): When removing object from

	global scope, wait for all lookups to finish afterwards.
	* elf/dl-open.c (add_to_global): When global scope array must
	grow, allocate a new one and free old array only after all
	lookups finish.
	* elf/dl-runtime.c (_dl_fixup): Protect using global scope.
	(_dl_lookup_symbol_x): Likewise.
	* elf/dl-support.c: Define _dl_wait_lookup_done.
	* sysdeps/generic/ldsodefs.h (struct rtld_global): Add
	_dl_wait_lookup_done.

1 files changed, 57 insertions, 0 deletions

diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 6b60642042..e556dbac08 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -996,3 +996,60 @@ __pthread_init_static_tls (struct link_map *map)
 
   lll_unlock (stack_cache_lock);
 }
+
+
+void
+attribute_hidden
+__wait_lookup_done (void)
+{
+  lll_lock (stack_cache_lock);
+
+  struct pthread *self = THREAD_SELF;
+
+  /* Iterate over the list with system-allocated threads first.  */
+  list_t *runp;
+  list_for_each (runp, &stack_used)
+    {
+      struct pthread *t = list_entry (runp, struct pthread, list);
+      if (t == self || t->header.gscope_flag == THREAD_GSCOPE_FLAG_UNUSED)
+	continue;
+
+      int *const gscope_flagp = &t->header.gscope_flag;
+
+      /* We have to wait until this thread is done with the global
+	 scope.  First tell the thread that we are waiting and
+	 possibly have to be woken.  */
+      if (atomic_compare_and_exchange_bool_acq (gscope_flagp,
+						THREAD_GSCOPE_FLAG_WAIT,
+						THREAD_GSCOPE_FLAG_USED))
+	continue;
+
+      do
+	lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT);
+      while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
+    }
+
+  /* Now the list with threads using user-allocated stacks.  */
+  list_for_each (runp, &__stack_user)
+    {
+      struct pthread *t = list_entry (runp, struct pthread, list);
+      if (t == self || t->header.gscope_flag == THREAD_GSCOPE_FLAG_UNUSED)
+	continue;
+
+      int *const gscope_flagp = &t->header.gscope_flag;
+
+      /* We have to wait until this thread is done with the global
+	 scope.  First tell the thread that we are waiting and
+	 possibly have to be woken.  */
+      if (atomic_compare_and_exchange_bool_acq (gscope_flagp,
+						THREAD_GSCOPE_FLAG_WAIT,
+						THREAD_GSCOPE_FLAG_USED))
+	continue;
+
+      do
+	lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT);
+      while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
+    }
+
+  lll_unlock (stack_cache_lock);
+}