[PATCH][BZ #13724] Do not segfault in pthread_setname_np (x, NULL)

[Ondřej Bílka]

Hi, this is another bug that could be handled quickly. Problem is if 
pthread_setname_np (x, NULL) should return error code or segfault. 
(see https://sourceware.org/bugzilla/show_bug.cgi?id=13724 )
If first is desired then following patch does it. If we choose for
second then close that bugzilla entry.

	* sysdeps/unix/sysv/linux/pthread_setname.c (pthread_setname_np):
	Handle null.

diff --git a/nptl/sysdeps/unix/sysv/linux/pthread_setname.c b/nptl/sysdeps/unix/sysv/linux/pthread_setname.c
index d6455dd..45eefa0 100644
--- a/nptl/sysdeps/unix/sysv/linux/pthread_setname.c
+++ b/nptl/sysdeps/unix/sysv/linux/pthread_setname.c
@@ -34,6 +34,10 @@ pthread_setname_np (th, name)
 {
   const struct pthread *pd = (const struct pthread *) th;
 
+  /* Return EFAULT like pthread_getname_np(x, NULL, 16) does.  */
+  if (name == NULL)
+    return EFAULT;
+
   /* Unfortunately the kernel headers do not export the TASK_COMM_LEN
      macro.  So we have to define it here.  */
 #define TASK_COMM_LEN 16