diff --git a/manual/memory.texi b/manual/memory.texi
index a1435aa..4731a38 100644
--- a/manual/memory.texi
+++ b/manual/memory.texi
@@ -3289,6 +3289,10 @@ in which memory protection keys are disabled.
 
 @item ENOSPC
 All available protection keys already have been allocated.
+
+The system does not implement memory protection keys or runs in a mode
+in which memory protection keys are disabled.
+
 @end table
 @end deftypefun
 
diff --git a/sysdeps/unix/sysv/linux/tst-pkey.c b/sysdeps/unix/sysv/linux/tst-pkey.c
index 600b6f0..40d7e9f 100644
--- a/sysdeps/unix/sysv/linux/tst-pkey.c
+++ b/sysdeps/unix/sysv/linux/tst-pkey.c
@@ -199,6 +199,10 @@ do_test (void)
       if (errno == EINVAL)
         FAIL_UNSUPPORTED
           ("CPU does not support memory protection keys: %m");
+      if (errno == ENOSPC)
+        FAIL_UNSUPPORTED
+          ("no keys available or kernel does not support memory"
+           " protection keys");
       FAIL_EXIT1 ("pkey_alloc: %m");
     }
   TEST_COMPARE (pkey_get (keys[0]), 0);