Fix reception of resume signal on process executing dirty

If a suspend/resume signal pair was sent to a process while it
was executing dirty the resume counter on the process got into
an inconsistent state. This in turn could cause the process
to enter a suspended state indefinitely.

1 files changed, 8 insertions, 2 deletions

diff --git a/erts/emulator/beam/erl_proc_sig_queue.c b/erts/emulator/beam/erl_proc_sig_queue.c
index 18418a76e1..c95b7057fd 100644
--- a/erts/emulator/beam/erl_proc_sig_queue.c
+++ b/erts/emulator/beam/erl_proc_sig_queue.c
@@ -3247,9 +3247,15 @@ erts_proc_sig_handle_incoming(Process *c_p, erts_aint32_t *statep,
                             erts_nif_demonitored((ErtsResource *) tmon->other.ptr);
                             cnt++;
                             break;
-                        case ERTS_MON_TYPE_SUSPEND:
-                            erts_resume(c_p, ERTS_PROC_LOCK_MAIN);
+                        case ERTS_MON_TYPE_SUSPEND: {
+                            ErtsMonitorSuspend *msp;
+                            erts_aint_t mstate;
+                            msp = (ErtsMonitorSuspend *) erts_monitor_to_data(tmon);
+                            mstate = erts_atomic_read_acqb(&msp->state);
+                            if (mstate & ERTS_MSUSPEND_STATE_FLG_ACTIVE)
+                                erts_resume(c_p, ERTS_PROC_LOCK_MAIN);
                             break;
+                        }
                         default:
                             break;
                         }