Merge branch 'rickard/multizero-timeout-in-timeout-fix/21/OTP-17253' into maint-21

* rickard/multizero-timeout-in-timeout-fix/21/OTP-17253:
  erts: Fix bug in timer wheel at cancel during bump yield
  erts: Tidy up some harmless code typos
  Fix multi-zero timeout callback handling in timer wheel

3 files changed, 67 insertions, 6 deletions

diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 51af067908..27bd734490 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -4416,6 +4416,28 @@ static void broken_halt_test(Eterm bif_arg_2)
     erts_exit(ERTS_DUMP_EXIT, "%T", bif_arg_2);
 }
 
+static void
+test_multizero_timeout_in_timeout3(void *vproc)
+{
+    Process *proc = (Process *) vproc;
+    ErtsMessage *mp = erts_alloc_message(0, NULL);
+    ERTS_DECL_AM(multizero_timeout_in_timeout_done);
+    erts_queue_message(proc, 0, mp, AM_multizero_timeout_in_timeout_done, am_system);
+    erts_proc_dec_refc(proc);
+}
+
+static void
+test_multizero_timeout_in_timeout2(void *vproc)
+{
+    erts_start_timer_callback(0, test_multizero_timeout_in_timeout3, vproc);
+}
+
+static void
+test_multizero_timeout_in_timeout(void *vproc)
+{
+    erts_start_timer_callback(0, test_multizero_timeout_in_timeout2, vproc);
+}
+
 BIF_RETTYPE erts_debug_set_internal_state_2(BIF_ALIST_2)
 {
     /*
@@ -4740,6 +4762,18 @@ BIF_RETTYPE erts_debug_set_internal_state_2(BIF_ALIST_2)
             BIF_P->mbuf_sz += sz;
             BIF_RET(copy);
         }
+        else if (ERTS_IS_ATOM_STR("multizero_timeout_in_timeout", BIF_ARG_1)) {
+            Sint64 timeout;
+            if (term_to_Sint64(BIF_ARG_2, &timeout)) {
+                if (timeout < 0)
+                    timeout = 0;
+                erts_proc_inc_refc(BIF_P);
+                erts_start_timer_callback((ErtsMonotonicTime) timeout,
+                                          test_multizero_timeout_in_timeout,
+                                          (void *) BIF_P);
+                BIF_RET(am_ok);
+            }
+        }
     }
 
     BIF_ERROR(BIF_P, BADARG);
diff --git a/erts/emulator/beam/time.c b/erts/emulator/beam/time.c
index a3069e419a..73538dc375 100644
--- a/erts/emulator/beam/time.c
+++ b/erts/emulator/beam/time.c
@@ -316,7 +316,7 @@ struct ErtsTimerWheel_ {
 #define ERTS_TW_SLOT_AT_ONCE (-1)
 
 #define ERTS_TW_BUMP_LATER_WHEEL(TIW) \
-    ((tiw)->pos + ERTS_TW_LATER_WHEEL_SLOT_SIZE >= (TIW)->later.pos)
+    ((TIW)->pos + ERTS_TW_LATER_WHEEL_SLOT_SIZE >= (TIW)->later.pos)
 
 static int bump_later_wheel(ErtsTimerWheel *tiw, int *yield_count_p);
 
@@ -480,6 +480,8 @@ find_next_timeout(ErtsSchedulerData *esdp, ErtsTimerWheel *tiw)
 
     ERTS_HARD_DBG_CHK_WHEELS(tiw, 0);
 
+    ERTS_TW_ASSERT(tiw->at_once.nto == 0);
+    ERTS_TW_ASSERT(tiw->nto == tiw->soon.nto + tiw->later.nto);
     ERTS_TW_ASSERT(tiw->yield_slot == ERTS_TW_SLOT_INACTIVE);
 
     if (tiw->nto == 0) { /* no timeouts in wheel */
@@ -701,7 +703,8 @@ remove_timer(ErtsTimerWheel *tiw, ErtsTWheelTimer *p)
         if (slot < ERTS_TW_SOON_WHEEL_END_SLOT) {
             if (empty_slot
                 && tiw->true_next_timeout_time
-                && p->timeout_pos == tiw->next_timeout_pos) {
+                && p->timeout_pos == tiw->next_timeout_pos
+                && tiw->yield_slot == ERTS_TW_SLOT_INACTIVE) {
                 tiw->true_next_timeout_time = 0;
             }
             if (--tiw->soon.nto == 0)
@@ -714,7 +717,8 @@ remove_timer(ErtsTimerWheel *tiw, ErtsTWheelTimer *p)
                 ErtsMonotonicTime tpos = tiw->later.min_tpos;
                 tpos &= ERTS_TW_LATER_WHEEL_POS_MASK;
                 tpos -= ERTS_TW_LATER_WHEEL_SLOT_SIZE;
-                if (tpos == tiw->next_timeout_pos)
+                if (tpos == tiw->next_timeout_pos
+                    && tiw->yield_slot == ERTS_TW_SLOT_INACTIVE)
                     tiw->true_next_timeout_time = 0;
             }
             if (--tiw->later.nto == 0) {
@@ -864,6 +868,8 @@ erts_bump_timers(ErtsTimerWheel *tiw, ErtsMonotonicTime curr_time)
 	    }
 
 	    if (tiw->pos >= bump_to) {
+                if (tiw->at_once.nto)
+                    continue;
                 ERTS_MSACC_POP_STATE_M_X();
 		break;
             }
@@ -908,7 +914,6 @@ erts_bump_timers(ErtsTimerWheel *tiw, ErtsMonotonicTime curr_time)
 
             {
                 ErtsMonotonicTime tmp_slots = bump_to - tiw->pos;
-                tmp_slots = (bump_to - tiw->pos);
                 if (tmp_slots < ERTS_TW_SOON_WHEEL_SIZE)
                     slots = (int) tmp_slots;
                 else
diff --git a/erts/emulator/test/timer_bif_SUITE.erl b/erts/emulator/test/timer_bif_SUITE.erl
index 4c25f067aa..71ab84edd6 100644
--- a/erts/emulator/test/timer_bif_SUITE.erl
+++ b/erts/emulator/test/timer_bif_SUITE.erl
@@ -31,7 +31,8 @@
 	 same_time_yielding_with_cancel/1, same_time_yielding_with_cancel_other/1,
 %	 same_time_yielding_with_cancel_other_accessor/1,
 	 auto_cancel_yielding/1,
-         suspended_scheduler_timeout/1]).
+         suspended_scheduler_timeout/1,
+         multizero_timeout_in_timeout/1]).
 
 -include_lib("common_test/include/ct.hrl").
 
@@ -70,7 +71,8 @@ all() ->
      same_time_yielding_with_cancel_other,
 %     same_time_yielding_with_cancel_other_accessor,
      auto_cancel_yielding,
-     suspended_scheduler_timeout].
+     suspended_scheduler_timeout,
+     multizero_timeout_in_timeout].
 
 
 %% Basic start_timer/3 functionality
@@ -657,6 +659,26 @@ suspended_scheduler_timeout(Config) when is_list(Config) ->
     end,
     ok.
 
+multizero_timeout_in_timeout(Config) when is_list(Config) ->
+    Timeout = 500,
+    MaxTimeoutDiff = 1000,
+
+    %% We want to operate on the same timer wheel all the time...
+    process_flag(scheduler, erlang:system_info(schedulers_online)),
+
+    erlang:send_after(5*(Timeout+MaxTimeoutDiff), self(), pling),
+    erlang:yield(),
+    Start = erlang:monotonic_time(),
+    erts_debug:set_internal_state(multizero_timeout_in_timeout, Timeout),
+    receive multizero_timeout_in_timeout_done -> ok end,
+    End = erlang:monotonic_time(),
+    Time = erlang:convert_time_unit(End-Start, native, millisecond),
+    io:format("Time=~p~n", [Time]),
+    true = Time < Timeout + MaxTimeoutDiff,
+    ok.
+            
+        
+
 process_is_cleaned_up(P) when is_pid(P) ->
     undefined == erts_debug:get_internal_state({process_status, P}).