Fix faulty use of thread progress in handle_aux_work()

As an optimization old thread progress data was kept and used in
handle_aux_work() in erl_process.c. This could cause memory to be
deallocated at a later time than intended, which is quite harmless.
This has, however, now been fixed.

1 files changed, 37 insertions, 15 deletions

diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 95d408f79d..854360f641 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -906,13 +906,13 @@ unset_aux_work_flags(ErtsSchedulerSleepInfo *ssi, erts_aint32_t flgs)
 #ifdef ERTS_SMP
 
 static ERTS_INLINE void
-thr_prgr_current_reset(ErtsAuxWorkData *awdp)
+haw_thr_prgr_current_reset(ErtsAuxWorkData *awdp)
 {
     awdp->current_thr_prgr = ERTS_THR_PRGR_INVALID;
 }
 
 static ERTS_INLINE ErtsThrPrgrVal
-thr_prgr_current(ErtsAuxWorkData *awdp)
+haw_thr_prgr_current(ErtsAuxWorkData *awdp)
 {
     ErtsThrPrgrVal current = awdp->current_thr_prgr;
     if (current == ERTS_THR_PRGR_INVALID) {
@@ -922,6 +922,21 @@ thr_prgr_current(ErtsAuxWorkData *awdp)
     return current;
 }
 
+static ERTS_INLINE void
+haw_thr_prgr_current_check_progress(ErtsAuxWorkData *awdp)
+{
+    ErtsThrPrgrVal current = awdp->current_thr_prgr;
+    if (current != ERTS_THR_PRGR_INVALID
+	&& !erts_thr_progress_equal(current, erts_thr_progress_current())) {
+	/*
+	 * We have used a previouly read current value that isn't the
+	 * latest; need to poke ourselfs in order to guarantee no loss
+	 * of wakeups.
+	 */
+	erts_sched_poke(awdp->ssi);
+    }
+}
+
 #endif
 
 typedef struct erts_misc_aux_work_t_ erts_misc_aux_work_t;
@@ -1020,7 +1035,7 @@ static ERTS_INLINE erts_aint32_t
 handle_misc_aux_work_thr_prgr(ErtsAuxWorkData *awdp,
 			      erts_aint32_t aux_work)
 {
-    if (!erts_thr_progress_has_reached_this(thr_prgr_current(awdp),
+    if (!erts_thr_progress_has_reached_this(haw_thr_prgr_current(awdp),
 					    awdp->misc.thr_prgr))
 	return aux_work & ~ERTS_SSI_AUX_WORK_MISC_THR_PRGR;
 
@@ -1125,7 +1140,7 @@ handle_async_ready_clean(ErtsAuxWorkData *awdp,
 
 #ifdef ERTS_SMP
     if (awdp->async_ready.need_thr_prgr
-	&& !erts_thr_progress_has_reached_this(thr_prgr_current(awdp),
+	&& !erts_thr_progress_has_reached_this(haw_thr_prgr_current(awdp),
 					       awdp->async_ready.thr_prgr)) {
 	return aux_work & ~ERTS_SSI_AUX_WORK_ASYNC_READY_CLEAN;
     }
@@ -1206,7 +1221,7 @@ handle_delayed_dealloc(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
 
     if (need_thr_progress) {
 	if (wakeup == ERTS_THR_PRGR_INVALID)
-	    wakeup = erts_thr_progress_later_than(thr_prgr_current(awdp));
+	    wakeup = erts_thr_progress_later(awdp->esdp);
 	awdp->dd.thr_prgr = wakeup;
 	set_aux_work_flags(ssi, ERTS_SSI_AUX_WORK_DD_THR_PRGR);
 	awdp->dd.thr_prgr = wakeup;
@@ -1227,7 +1242,7 @@ handle_delayed_dealloc_thr_prgr(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
     int need_thr_progress;
     int more_work;
     ErtsThrPrgrVal wakeup = ERTS_THR_PRGR_INVALID;
-    ErtsThrPrgrVal current = thr_prgr_current(awdp);
+    ErtsThrPrgrVal current = haw_thr_prgr_current(awdp);
 
     if (!erts_thr_progress_has_reached_this(current, awdp->dd.thr_prgr))
 	return aux_work & ~ERTS_SSI_AUX_WORK_DD_THR_PRGR;
@@ -1249,7 +1264,7 @@ handle_delayed_dealloc_thr_prgr(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
 
     if (need_thr_progress) {
 	if (wakeup == ERTS_THR_PRGR_INVALID)
-	    wakeup = erts_thr_progress_later_than(current);
+	    wakeup = erts_thr_progress_later(awdp->esdp);
 	awdp->dd.thr_prgr = wakeup;
 	erts_thr_progress_wakeup(awdp->esdp, wakeup);
     }
@@ -1438,7 +1453,7 @@ handle_setup_aux_work_timer(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
 }
 
 static erts_aint32_t
-handle_aux_work(ErtsAuxWorkData *awdp, erts_aint32_t orig_aux_work)
+handle_aux_work(ErtsAuxWorkData *awdp, erts_aint32_t orig_aux_work, int waiting)
 {
 #undef HANDLE_AUX_WORK
 #define HANDLE_AUX_WORK(FLG, HNDLR) \
@@ -1456,7 +1471,7 @@ handle_aux_work(ErtsAuxWorkData *awdp, erts_aint32_t orig_aux_work)
     erts_aint32_t ignore = 0;
 
 #ifdef ERTS_SMP
-    thr_prgr_current_reset(awdp);
+    haw_thr_prgr_current_reset(awdp);
 #endif
 
     ERTS_DBG_CHK_AUX_WORK_VAL(aux_work);
@@ -1522,6 +1537,11 @@ handle_aux_work(ErtsAuxWorkData *awdp, erts_aint32_t orig_aux_work)
 
     ERTS_DBG_CHK_AUX_WORK_VAL(aux_work);
 
+#ifdef ERTS_SMP
+    if (waiting && !aux_work)
+	haw_thr_prgr_current_check_progress(awdp);
+#endif
+
     return aux_work;
 
 #undef HANDLE_AUX_WORK
@@ -1982,7 +2002,7 @@ aux_thread(void *unused)
 	if (aux_work) {
 	    if (!thr_prgr_active)
 		erts_thr_progress_active(NULL, thr_prgr_active = 1);
-	    aux_work = handle_aux_work(awdp, aux_work);
+	    aux_work = handle_aux_work(awdp, aux_work, 1);
 	    if (aux_work && erts_thr_progress_update(NULL))
 		erts_thr_progress_leader_update(NULL);
 	}
@@ -2061,7 +2081,7 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 		    erts_thr_progress_active(esdp, thr_prgr_active = 1);
 		    sched_wall_time_change(esdp, 1);
 		}
-		aux_work = handle_aux_work(&esdp->aux_work_data, aux_work);
+		aux_work = handle_aux_work(&esdp->aux_work_data, aux_work, 1);
 		if (aux_work && erts_thr_progress_update(esdp))
 		    erts_thr_progress_leader_update(esdp);
 	    }
@@ -2163,7 +2183,7 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 		if (!thr_prgr_active)
 		    erts_thr_progress_active(esdp, thr_prgr_active = 1);
 #endif
-		aux_work = handle_aux_work(&esdp->aux_work_data, aux_work);
+		aux_work = handle_aux_work(&esdp->aux_work_data, aux_work, 1);
 #ifdef ERTS_SMP
 		if (aux_work && erts_thr_progress_update(esdp))
 		    erts_thr_progress_leader_update(esdp);
@@ -4170,7 +4190,9 @@ suspend_scheduler(ErtsSchedulerData *esdp)
 			erts_thr_progress_active(esdp, thr_prgr_active = 1);
 			sched_wall_time_change(esdp, 1);
 		    }
-		    aux_work = handle_aux_work(&esdp->aux_work_data, aux_work);
+		    aux_work = handle_aux_work(&esdp->aux_work_data,
+					       aux_work,
+					       1);
 		    if (aux_work && erts_thr_progress_update(esdp))
 			erts_thr_progress_leader_update(esdp);
 		}
@@ -6412,7 +6434,7 @@ Process *schedule(Process *p, int calls)
 		if (leader_update)
 		    erts_thr_progress_leader_update(esdp);
 		if (aux_work)
-		    handle_aux_work(&esdp->aux_work_data, aux_work);
+		    handle_aux_work(&esdp->aux_work_data, aux_work, 0);
 		erts_smp_runq_lock(rq);
 	    }
 	}
@@ -6425,7 +6447,7 @@ Process *schedule(Process *p, int calls)
 	    erts_aint32_t aux_work;
 	    aux_work = erts_atomic32_read_acqb(&esdp->ssi->aux_work);
 	    if (aux_work)
-		handle_aux_work(&esdp->aux_work_data, aux_work);
+		handle_aux_work(&esdp->aux_work_data, aux_work, 0);
 	}
 #endif /* ERTS_SMP */