From 7f9707b67c0a460bc56aa25b436681fbbdc2d004 Mon Sep 17 00:00:00 2001
From: Thomas Applencourt
 <applenco@aurora-uan-0009.hostmgmt.cm.aurora.alcf.anl.gov>
Date: Tue, 3 Sep 2024 16:22:23 +0000
Subject: [PATCH] fix race condition

---
 integration_tests/light_iprof_only_sync.sh | 38 ++++++++++++----------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/integration_tests/light_iprof_only_sync.sh b/integration_tests/light_iprof_only_sync.sh
index 5c7a4623..908c7ace 100755
--- a/integration_tests/light_iprof_only_sync.sh
+++ b/integration_tests/light_iprof_only_sync.sh
@@ -10,11 +10,9 @@ RT_SIGNAL_GLOBAL_BARRIER=$((SIGRTMIN + 1))
 RT_SIGNAL_LOCAL_BARRIER=$((SIGRTMIN + 2))
 RT_SIGNAL_FINISH=$((SIGRTMIN + 3))
 
-# Initialize a variable to track signal reception
-SIGNAL_RECEIVED="false"
 # Signal handler for capturing signals
 handle_signal() {
-    echo "$PARENT_PID |   Received signal $1 from mpi_daemon"
+    echo "$PARENT_PID $(date) |   Received signal $1 from mpi_daemon"
     if [ "$1" == "RT_SIGNAL_READY" ]; then
         SIGNAL_RECEIVED="true"
     fi
@@ -25,36 +23,40 @@ trap 'handle_signal RT_SIGNAL_READY' $RT_SIGNAL_READY
 
 # Function to wait for RT_SIGNAL_READY
 wait_for_signal() {
-    SIGNAL_RECEIVED="false"
     while [[ "$SIGNAL_RECEIVED" == "false" ]]; do
         sleep 0.1  # Small sleep to prevent busy looping
     done
 }
 
-# Function to send signals, using adjusted SIGRTMIN corresponding to MPI signal daemon defines
+# To avoid race condition, `SIGNAL_RECEIVED` need to be set
+#   before spawning or signaling the daemon
+spawn_daemon_blocking() {
+    local parent_pid=$$
+    SIGNAL_RECEIVED="false"
+    "${THAPI_BIN_DIR}"/sync_daemon_"${THAPI_SYNC_DAEMON}" parent_pid &
+    DAEMON_PID=$!
+    wait_for_signal
+}
+
 send_signal_blocking() {
-    kill -$1 $DAEMON_PID
+    SIGNAL_RECEIVED="false"
+    kill -"$1" $DAEMON_PID
     wait_for_signal
 }
 
-# Get the PID of this script
-PARENT_PID=$$
-# Start sync daemon in the background
-${THAPI_BIN_DIR}/sync_daemon_${THAPI_SYNC_DAEMON} $PARENT_PID &
-DAEMON_PID=$!
-echo "$PARENT_PID | Wait for daemon to be ready"
-wait_for_signal
-echo "$PARENT_PID | Send Local Barrier signal"
+echo "$PARENT_PID $(date) | Spawn Daemon"
+spawn_daemon_blocking
+echo "$PARENT_PID $(date) | Send Local Barrier signal"
 send_signal_blocking $RT_SIGNAL_LOCAL_BARRIER
 # Run test program
 "$@"
 
 # Final synchronization after mpi_hello_world execution
-echo "$PARENT_PID | Send Local Barrier signal"
+echo "$PARENT_PID $(date) | Send Local Barrier signal"
 send_signal_blocking $RT_SIGNAL_LOCAL_BARRIER
-echo "$PARENT_PID | Send Global Barrier signal"
+echo "$PARENT_PID $(date) | Send Global Barrier signal"
 send_signal_blocking $RT_SIGNAL_GLOBAL_BARRIER
-echo "$PARENT_PID | Send Termination signal"
+echo "$PARENT_PID $(date) | Send Termination signal"
 send_signal_blocking $RT_SIGNAL_FINISH
-echo "$PARENT_PID | Wait for daemon to quit"
+echo "$PARENT_PID $(date) | Wait for daemon to quit"
 wait $DAEMON_PID