Downstream patch only.

Revert changes made to elf/dl-readonly-area.c compared to
ed6a68bac7cd056abda9008019c71b167f0362dc since `_dl_find_object` has
been backported.

Note: `_dl_find_object` isn't directly made available internally
downstream, we can use `__dl_find_object_internal` instead.

diff --git a/elf/dl-readonly-area.c b/elf/dl-readonly-area.c
index 570b99b11527db13..3b39eed06a379ce3 100644
--- a/elf/dl-readonly-area.c
+++ b/elf/dl-readonly-area.c
@@ -40,16 +40,11 @@ check_relro (const struct link_map *l, uintptr_t start, uintptr_t end)
 enum dl_readonly_area_error_type
 _dl_readonly_area (const void *ptr, size_t size)
 {
-  /* Protect against concurrent loads and unloads.  */
-  __rtld_lock_lock_recursive (GL(dl_load_lock));
-
-  const struct link_map *l = _dl_find_dso_for_object ((ElfW(Addr)) ptr);
-
-  __rtld_lock_unlock_recursive (GL(dl_load_lock));
-
-  if (l == NULL)
+  struct dl_find_object dlfo;
+  if (__dl_find_object_internal ((void *)ptr, &dlfo) != 0)
     return dl_readonly_area_not_found;
 
+  const struct link_map *l = dlfo.dlfo_link_map;
   uintptr_t ptr_start = (uintptr_t) ptr;
   uintptr_t ptr_end = ptr_start + size;