Fixed

tests/queries/0_stateless/02558_system_processes_elapsed.sh

@@ -9,7 +9,12 @@ while :; do
     pid=$!
     sleep 1.5
     duration="$($CLICKHOUSE_CLIENT -q "select floor(elapsed) from system.processes where current_database = currentDatabase() and query not like '%system.processes%'")"
-    kill -INT $pid
+    # The process might not exist at this point in some exception situations
+    # maybe it was killed by OOM?
+    # It safe to skip this iteration.
+    if ! kill -INT $pid > /dev/null 2>&1; then
+        continue
+    fi
     wait
     $CLICKHOUSE_CLIENT -q "kill query where current_database = currentDatabase() sync format Null"
     if [[ $duration -eq 1 ]]; then