Re: lib/49006: thread specific storage not always initialized to NULL

[Tony Cook <tony%develop-help.com@localhost>]

The following reply was made to PR lib/49006; it has been noted by GNATS.

From: Tony Cook <tony%develop-help.com@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: lib-bug-people%NetBSD.org@localhost, gnats-admin%NetBSD.org@localhost, 
netbsd-bugs%NetBSD.org@localhost
Subject: Re: lib/49006: thread specific storage not always initialized to NULL
Date: Mon, 21 Jul 2014 10:09:22 +1000

 On Thu, Jul 17, 2014 at 10:45:00AM +0000, Martin Husemann wrote:
 > The following reply was made to PR lib/49006; it has been noted by GNATS.
 > 
 > From: Martin Husemann <martin%duskware.de@localhost>
 > To: gnats-bugs%NetBSD.org@localhost
 > Cc: 
 > Subject: Re: lib/49006: thread specific storage not always initialized to 
 > NULL
 > Date: Thu, 17 Jul 2014 12:40:58 +0200
 > 
 >  This seems to work correctly in -current.
 
 Looks like it was fixed in this chunk of v1.9 [1] of
 /lib/libpthread/pthread_tsd.c:
 
 @@ -206,17 +294,24 @@ pthread__destroy_tsd(pthread_t self)
        do {
                done = 1;
                for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
 -                      if (self->pt_specific[i] != NULL) {
 -                              pthread_mutex_lock(&tsd_mutex);
 +                      struct pt_specific *pt = &self->pt_specific[i];
 +                      if (pt->pts_next.ptqe_prev == NULL)
 +                              continue;
 +                      pthread_mutex_lock(&tsd_mutex);
 +
 +                      if (pt->pts_next.ptqe_prev != NULL)  {
 +                              PTQ_REMOVE(&pthread__tsd_list[i], pt, pts_next);
 +                              val = pt->pts_value;
 +                              pt->pts_value = NULL;
 +                              pt->pts_next.ptqe_prev = NULL;
                                destructor = pthread__tsd_destructors[i];
 -                              pthread_mutex_unlock(&tsd_mutex);
 -                              if (destructor != NULL) {
 -                                      done = 0;
 -                                      val = self->pt_specific[i];
 -                                      /* See above */
 -                                      self->pt_specific[i] = NULL;
 -                                      (*destructor)(val);
 -                              }
 +                      } else
 +                              destructor = NULL;
 +
 +                      pthread_mutex_unlock(&tsd_mutex);
 +                      if (destructor != NULL) {
 +                              done = 0;
 +                              (*destructor)(val);
                        }
                }
        } while (!done && iterations--);
 
 The removed code only set self->pt_specific[i] to NULL when the entry
 has a destructor, the new code doesn't have that flaw, assuming I
 understand it.
 
 Thanks,
 Tony
 
 [1] 
http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/libpthread/pthread_tsd.c.diff?r1=1.8&r2=1.9&only_with_tag=MAIN