Trivial changes for thread sanitizer

Thread sanitizer warns about reads and writes of variables that are
meant to be read without holding a lock:

* Global "keep_going" is now a ddsrt_atomic_uint32_t

* Thread "vtime" is now a ddsrt_atomic_uint32_t

Previously the code relied on the assumption that a 32-bit int would be
treated as atomic, now that is all wrapped in ddsrt_atomic_{ld,st}32.
These being inline functions doing exactly the same thing, there is no
functional change, but it does allow annotating the loads and stores for
via function attributes on the ddsrt_atomic_{ld,st}X.

The concurrent hashtable implementation is replaced by a locked version
of the non-concurrent implementation if thread sanitizer is used.  This
changes eliminates the scores of problems signalled by thread sanitizer
in the GUID-to-entity translation and the key-to-instance id lookups.

Other than that, this replaces a flag used in a waitset test case to be
a ddsrt_atomic_uint32_t.

Signed-off-by: Erik Boasson <eb@ilities.com>

src/core/ddsi/include/dds/ddsi/q_globals.h

@@ -221,7 +221,7 @@ struct q_globals {
   struct thread_state1 *listen_ts;
 
   /* Flag cleared when stopping (receive threads). FIXME. */
-  int rtps_keepgoing;
+  ddsrt_atomic_uint32_t rtps_keepgoing;
 
   /* Start time of the DDSI2 service, for logging relative time stamps,
      should I ever so desire. */

src/core/ddsi/include/dds/ddsi/q_thread.h

@@ -57,13 +57,14 @@ enum thread_state {
 struct logbuf;
 
 /*
- * watchdog indicates progress for the service lease liveliness mechsanism, while vtime
- * indicates progress for the Garbage collection purposes.
- *  vtime even : thread awake
- *  vtime odd  : thread asleep
+ * vtime indicates progress for the garbage collector and the liveliness monitoring.
+ *
+ * vtime is updated without using atomic operations: only the owning thread updates
+ * them, and the garbage collection mechanism and the liveliness monitoring only
+ * observe the value
  */
 #define THREAD_BASE                             \
-  volatile vtime_t vtime;                       \
+  ddsrt_atomic_uint32_t vtime;                  \
   ddsrt_thread_t tid;                           \
   ddsrt_thread_t extTid;                        \
   enum thread_state state;                      \
@@ -131,17 +132,21 @@ DDS_EXPORT inline bool vtime_gt (vtime_t vtime1, vtime_t vtime0)
 
 DDS_EXPORT inline bool thread_is_awake (void)
 {
-  return vtime_awake_p (lookup_thread_state ()->vtime);
+  struct thread_state1 *ts = lookup_thread_state ();
+  vtime_t vt = ddsrt_atomic_ld32 (&ts->vtime);
+  return vtime_awake_p (vt);
 }
 
 DDS_EXPORT inline bool thread_is_asleep (void)
 {
-  return vtime_asleep_p (lookup_thread_state ()->vtime);
+  struct thread_state1 *ts = lookup_thread_state ();
+  vtime_t vt = ddsrt_atomic_ld32 (&ts->vtime);
+  return vtime_asleep_p (vt);
 }
 
 DDS_EXPORT inline void thread_state_asleep (struct thread_state1 *ts1)
 {
-  vtime_t vt = ts1->vtime;
+  vtime_t vt = ddsrt_atomic_ld32 (&ts1->vtime);
   assert (vtime_awake_p (vt));
   /* nested calls a rare and an extra fence doesn't break things */
   ddsrt_atomic_fence_rel ();
@@ -149,24 +154,24 @@ DDS_EXPORT inline void thread_state_asleep (struct thread_state1 *ts1)
     vt += (1u << VTIME_TIME_SHIFT) - 1u;
   else
     vt -= 1u;
-  ts1->vtime = vt;
+  ddsrt_atomic_st32 (&ts1->vtime, vt);
 }
 
 DDS_EXPORT inline void thread_state_awake (struct thread_state1 *ts1)
 {
-  vtime_t vt = ts1->vtime;
+  vtime_t vt = ddsrt_atomic_ld32 (&ts1->vtime);
   assert ((vt & VTIME_NEST_MASK) < VTIME_NEST_MASK);
-  ts1->vtime = vt + 1u;
+  ddsrt_atomic_st32 (&ts1->vtime, vt + 1u);
   /* nested calls a rare and an extra fence doesn't break things */
   ddsrt_atomic_fence_acq ();
 }
 
 DDS_EXPORT inline void thread_state_awake_to_awake_no_nest (struct thread_state1 *ts1)
 {
-  vtime_t vt = ts1->vtime;
+  vtime_t vt = ddsrt_atomic_ld32 (&ts1->vtime);
   assert ((vt & VTIME_NEST_MASK) == 1);
   ddsrt_atomic_fence_rel ();
-  ts1->vtime = vt + (1u << VTIME_TIME_SHIFT);
+  ddsrt_atomic_st32 (&ts1->vtime, vt + (1u << VTIME_TIME_SHIFT));
   ddsrt_atomic_fence_acq ();
 }
 

src/core/ddsi/src/ddsi_tcp.c

@@ -706,6 +706,7 @@ static ddsrt_socket_t ddsi_tcp_conn_handle (ddsi_tran_base_t base)
   return ((ddsi_tcp_conn_t) base)->m_sock;
 }
 
+ddsrt_attribute_no_sanitize (("thread"))
 static bool ddsi_tcp_supports (int32_t kind)
 {
   return kind == ddsi_tcp_factory_g.m_kind;
@@ -770,7 +771,7 @@ static ddsi_tran_conn_t ddsi_tcp_accept (ddsi_tran_listener_t listener)
     {
       rc = ddsrt_accept(tl->m_sock, NULL, NULL, &sock);
     }
-    if (! gv.rtps_keepgoing)
+    if (!ddsrt_atomic_ld32(&gv.rtps_keepgoing))
     {
       ddsi_tcp_sock_free (sock, NULL);
       return NULL;

src/core/ddsi/src/ddsi_threadmon.c

@@ -83,7 +83,7 @@ static uint32_t threadmon_thread (struct ddsi_threadmon *sl)
           n_unused++;
         else
         {
-          vtime_t vt = thread_states.ts[i].vtime;
+          vtime_t vt = ddsrt_atomic_ld32 (&thread_states.ts[i].vtime);
           bool alive = vtime_asleep_p (vt) || vtime_asleep_p (sl->av_ary[i].vt) || vtime_gt (vt, sl->av_ary[i].vt);
           n_alive += (unsigned) alive;
           DDS_TRACE(" %u(%s):%c:%"PRIx32"->%"PRIx32, i, thread_states.ts[i].name, alive ? 'a' : 'd', sl->av_ary[i].vt, vt);

src/core/ddsi/src/ddsi_tran.c

@@ -91,6 +91,7 @@ static ddsi_tran_factory_t ddsi_factory_find_with_len (const char * type, size_t
   return factory;
 }
 
+ddsrt_attribute_no_sanitize (("thread"))
 ddsi_tran_factory_t ddsi_factory_find_supported_kind (int32_t kind)
 {
   /* FIXME: MUST speed up */
@@ -124,7 +125,7 @@ void ddsi_conn_free (ddsi_tran_conn_t conn)
         for (uint32_t i = 0; i < gv.n_recv_threads; i++)
         {
           if (!gv.recv_threads[i].ts)
-            assert (!gv.rtps_keepgoing);
+            assert (!ddsrt_atomic_ld32 (&gv.rtps_keepgoing));
           else
           {
             switch (gv.recv_threads[i].arg.mode)

src/core/ddsi/src/q_gc.c

@@ -44,7 +44,7 @@ static void threads_vtime_gather_for_wait (unsigned *nivs, struct idx_vtime *ivs
   uint32_t i, j;
   for (i = j = 0; i < thread_states.nthreads; i++)
   {
-    vtime_t vtime = thread_states.ts[i].vtime;
+    vtime_t vtime = ddsrt_atomic_ld32 (&thread_states.ts[i].vtime);
     if (vtime_awake_p (vtime))
     {
       ivs[j].idx = i;
@@ -63,7 +63,7 @@ static int threads_vtime_check (uint32_t *nivs, struct idx_vtime *ivs)
   while (i < *nivs)
   {
     uint32_t thridx = ivs[i].idx;
-    vtime_t vtime = thread_states.ts[thridx].vtime;
+    vtime_t vtime = ddsrt_atomic_ld32 (&thread_states.ts[thridx].vtime);
     assert (vtime_awake_p (ivs[i].vtime));
     if (!vtime_gt (vtime, ivs[i].vtime))
       ++i;

src/core/ddsi/src/q_init.c

@@ -679,9 +679,9 @@ static void rtps_term_prep (void)
 {
   /* Stop all I/O */
   ddsrt_mutex_lock (&gv.lock);
-  if (gv.rtps_keepgoing)
+  if (ddsrt_atomic_ld32 (&gv.rtps_keepgoing))
   {
-    gv.rtps_keepgoing = 0; /* so threads will stop once they get round to checking */
+    ddsrt_atomic_st32 (&gv.rtps_keepgoing, 0); /* so threads will stop once they get round to checking */
     ddsrt_atomic_fence ();
     /* can't wake up throttle_writer, currently, but it'll check every few seconds */
     trigger_recv_threads ();
@@ -1252,7 +1252,7 @@ int rtps_init (void)
 
   gv.gcreq_queue = gcreq_queue_new ();
 
-  gv.rtps_keepgoing = 1;
+  ddsrt_atomic_st32 (&gv.rtps_keepgoing, 1);
   ddsrt_rwlock_init (&gv.qoslock);
 
   if (config.xpack_send_async)

src/core/ddsi/src/q_receive.c

@@ -3156,7 +3156,7 @@ uint32_t listen_thread (struct ddsi_tran_listener * listener)
 {
   ddsi_tran_conn_t conn;
 
-  while (gv.rtps_keepgoing)
+  while (ddsrt_atomic_ld32 (&gv.rtps_keepgoing))
   {
     /* Accept connection from listener */
 
@@ -3310,7 +3310,7 @@ uint32_t recv_thread (void *vrecv_thread_arg)
   nn_rbufpool_setowner (rbpool, ddsrt_thread_self ());
   if (waitset == NULL)
   {
-    while (gv.rtps_keepgoing)
+    while (ddsrt_atomic_ld32 (&gv.rtps_keepgoing))
     {
       LOG_THREAD_CPUTIME (next_thread_cputime);
       (void) do_packet (ts1, recv_thread_arg->u.single.conn, NULL, rbpool);
@@ -3343,7 +3343,7 @@ uint32_t recv_thread (void *vrecv_thread_arg)
       num_fixed += (unsigned)rc;
     }
 
-    while (gv.rtps_keepgoing)
+    while (ddsrt_atomic_ld32 (&gv.rtps_keepgoing))
     {
       int rebuildws;
       LOG_THREAD_CPUTIME (next_thread_cputime);

src/core/ddsi/src/q_thread.c

@@ -75,7 +75,7 @@ static void ddsrt_free_aligned (void *ptr)
 void thread_states_init_static (void)
 {
   static struct thread_state1 ts = {
-    .state = THREAD_STATE_ALIVE, .vtime = 0u, .name = "(anon)"
+    .state = THREAD_STATE_ALIVE, .vtime = DDSRT_ATOMIC_UINT32_INIT (0), .name = "(anon)"
   };
   tsd_thread_state = &ts;
 }
@@ -92,7 +92,7 @@ void thread_states_init (unsigned maxthreads)
   for (uint32_t i = 0; i < thread_states.nthreads; i++)
   {
     thread_states.ts[i].state = THREAD_STATE_ZERO;
-    thread_states.ts[i].vtime = 0u;
+    ddsrt_atomic_st32 (&thread_states.ts[i].vtime, 0);
     thread_states.ts[i].name = NULL;
   }
   DDSRT_WARNING_MSVC_ON(6386);
@@ -113,6 +113,7 @@ void thread_states_fini (void)
   thread_states.ts = NULL;
 }
 
+ddsrt_attribute_no_sanitize (("thread"))
 static struct thread_state1 *find_thread_state (ddsrt_thread_t tid)
 {
   if (thread_states.ts) {
@@ -132,7 +133,7 @@ static void cleanup_thread_state (void *data)
   if (ts)
   {
     assert(ts->state == THREAD_STATE_LAZILY_CREATED);
-    assert(vtime_asleep_p(ts->vtime));
+    assert(vtime_asleep_p(ddsrt_atomic_ld32 (&ts->vtime)));
     reset_thread_state(ts);
   }
   ddsrt_fini();
@@ -207,7 +208,7 @@ void upgrade_main_thread (void)
     abort ();
   ts1 = &thread_states.ts[cand];
   if (ts1->state == THREAD_STATE_ZERO)
-    assert (vtime_asleep_p (ts1->vtime));
+    assert (vtime_asleep_p (ddsrt_atomic_ld32 (&ts1->vtime)));
   ts1->state = THREAD_STATE_LAZILY_CREATED;
   ts1->tid = ddsrt_thread_self ();
   ts1->name = main_thread_name;
@@ -233,7 +234,7 @@ static struct thread_state1 *init_thread_state (const char *tname, enum thread_s
     return NULL;
 
   ts = &thread_states.ts[cand];
-  assert (vtime_asleep_p (ts->vtime));
+  assert (vtime_asleep_p (ddsrt_atomic_ld32 (&ts->vtime)));
   ts->name = ddsrt_strdup (tname);
   ts->state = state;
 
@@ -300,7 +301,7 @@ dds_return_t join_thread (struct thread_state1 *ts1)
   dds_return_t ret;
   assert (ts1->state == THREAD_STATE_ALIVE);
   ret = ddsrt_thread_join (ts1->extTid, NULL);
-  assert (vtime_asleep_p (ts1->vtime));
+  assert (vtime_asleep_p (ddsrt_atomic_ld32 (&ts1->vtime)));
   reap_thread_state (ts1, 1);
   return ret;
 }
@@ -317,7 +318,7 @@ void reset_thread_state (struct thread_state1 *ts1)
 void downgrade_main_thread (void)
 {
   struct thread_state1 *ts1 = lookup_thread_state ();
-  assert (vtime_asleep_p (ts1->vtime));
+  assert (vtime_asleep_p (ddsrt_atomic_ld32 (&ts1->vtime)));
   /* no need to sync with service lease: already stopped */
   reap_thread_state (ts1, 0);
   thread_states_init_static ();

src/core/ddsi/src/q_transmit.c

@@ -968,7 +968,7 @@ static dds_return_t throttle_writer (struct thread_state1 * const ts1, struct nn
     whc_get_state (wr->whc, &whcst);
   }
 
-  while (gv.rtps_keepgoing && !writer_may_continue (wr, &whcst))
+  while (ddsrt_atomic_ld32 (&gv.rtps_keepgoing) && !writer_may_continue (wr, &whcst))
   {
     int64_t reltimeout;
     tnow = now_mt ();

src/core/ddsi/src/q_xevent.c

@@ -597,8 +597,8 @@ static void handle_xevk_heartbeat (struct nn_xpack *xp, struct xevent *ev, nn_mt
     return;
   }
 
-  assert (wr->reliable);
   ddsrt_mutex_lock (&wr->e.lock);
+  assert (wr->reliable);
   whc_get_state(wr->whc, &whcst);
   if (!writer_must_have_hb_scheduled (wr, &whcst))
   {