[3.0] d420192 Fix a race condition, the child thread could get to the first assert before the parent carried out the assignment of the thread id to the variable.

[Tollef Fog Heen]

commit d4201928a2b86858810d149293c4b754d612ed01
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Wed Aug 22 10:01:19 2012 +0000

    Fix a race condition, the child thread could get to the first
    assert before the parent carried out the assignment of the thread
    id to the variable.
    
    Detected by:	OSX

diff --git a/bin/varnishd/storage_persistent.c b/bin/varnishd/storage_persistent.c
index a4ba598..8acbc20 100644
--- a/bin/varnishd/storage_persistent.c
+++ b/bin/varnishd/storage_persistent.c
@@ -275,6 +275,7 @@ smp_thread(struct sess *sp, void *priv)
 
 	(void)sp;
 	CAST_OBJ_NOTNULL(sc, priv, SMP_SC_MAGIC);
+	sc->thread = pthread_self();
 
 	/* First, load all the objects from all segments */
 	VTAILQ_FOREACH(sg, &sc->segments, list)
@@ -306,6 +307,7 @@ static void
 smp_open(const struct stevedore *st)
 {
 	struct smp_sc	*sc;
+	pthread_t pt;
 
 	ASSERT_CLI();
 
@@ -347,7 +349,7 @@ smp_open(const struct stevedore *st)
 	smp_new_seg(sc);
 
 	/* Start the worker silo worker thread, it will load the objects */
-	WRK_BgThread(&sc->thread, "persistence", smp_thread, sc);
+	WRK_BgThread(&pt, "persistence", smp_thread, sc);
 
 	VTAILQ_INSERT_TAIL(&silos, sc, list);
 	Lck_Unlock(&sc->mtx);