Handles the masked signal when the thread exits

[Florian Weimer]

* Gibeom Gwon:

> I hit Ctrl+C in the middle of running signal program. You can see
> ^C and sigint:.. printed in my result.

I see it now.  It's a real bug.  It only happens with cancellation.

Would yo umind filing a bug here?

  <https://sourceware.org/bugzilla/enter_bug.cgi?product=glibc&component=nptl>

The fix should look something like this:

diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
index d6ea43a754..bad9eeb52f 100644
--- a/nptl/pthread_create.c
+++ b/nptl/pthread_create.c
@@ -406,8 +406,6 @@ start_thread (void *arg)
   unwind_buf.priv.data.prev = NULL;
   unwind_buf.priv.data.cleanup = NULL;
 
-  __libc_signal_restore_set (&pd->sigmask);
-
   /* Allow setxid from now onwards.  */
   if (__glibc_unlikely (atomic_exchange_acq (&pd->setxid_futex, 0) == -2))
     futex_wake (&pd->setxid_futex, 1, FUTEX_PRIVATE);
@@ -417,6 +415,8 @@ start_thread (void *arg)
       /* Store the new cleanup handler info.  */
       THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
 
+      __libc_signal_restore_set (&pd->sigmask);
+
       LIBC_PROBE (pthread_start, 3, (pthread_t) pd, pd->start_routine, pd->arg);
 
       /* Run the code the user provided.  */

Thanks,
Florian