diff --git a/debian/clickhouse-server.init b/debian/clickhouse-server.init
index 3c5b6edc05d..b82c70bd6e0 100755
--- a/debian/clickhouse-server.init
+++ b/debian/clickhouse-server.init
@@ -76,7 +76,7 @@ is_supported_command()
 
 is_running()
 {
-    [ -r "$CLICKHOUSE_PIDFILE" ] && pgrep -s $(cat "$CLICKHOUSE_PIDFILE") 1> /dev/null 2> /dev/null
+    pgrep --pidfile "$CLICKHOUSE_PIDFILE" $(echo "${PROGRAM}" | cut -c1-15) 1> /dev/null 2> /dev/null
 }
 
 
diff --git a/docker/test/stress/run.sh b/docker/test/stress/run.sh
index 793191b08da..47c8603babb 100755
--- a/docker/test/stress/run.sh
+++ b/docker/test/stress/run.sh
@@ -8,7 +8,19 @@ dpkg -i package_folder/clickhouse-server_*.deb
 dpkg -i package_folder/clickhouse-client_*.deb
 dpkg -i package_folder/clickhouse-test_*.deb
 
-function wait_server()
+function stop()
+{
+    timeout 120 service clickhouse-server stop
+
+    # Wait for process to disappear from processlist and also try to kill zombies.
+    while kill -9 $(pidof clickhouse-server)
+    do
+        echo "Killed clickhouse-server"
+        sleep 0.5
+    done
+}
+
+function start()
 {
     counter=0
     until clickhouse-client --query "SELECT 1"
@@ -18,9 +30,10 @@ function wait_server()
             echo "Cannot start clickhouse-server"
             cat /var/log/clickhouse-server/stdout.log
             tail -n1000 /var/log/clickhouse-server/stderr.log
-            tail -n1000 /var/log/clickhouse-server/clickhouse-server.err.log
+            tail -n1000 /var/log/clickhouse-server/clickhouse-server.log
             break
         fi
+        timeout 120 service clickhouse-server start
         sleep 0.5
         counter=$(($counter + 1))
     done
@@ -34,19 +47,15 @@ echo "TSAN_OPTIONS='halt_on_error=1 history_size=7 ignore_noninstrumented_module
 echo "UBSAN_OPTIONS='print_stacktrace=1'" >> /etc/environment
 echo "ASAN_OPTIONS='malloc_context_size=10 verbosity=1 allocator_release_to_os_interval_ms=10000'" >> /etc/environment
 
-timeout 120 service clickhouse-server start
-
-wait_server
+start
 
 /s3downloader --dataset-names $DATASETS
 chmod 777 -R /var/lib/clickhouse
 clickhouse-client --query "ATTACH DATABASE IF NOT EXISTS datasets ENGINE = Ordinary"
 clickhouse-client --query "CREATE DATABASE IF NOT EXISTS test"
 
-timeout 120 service clickhouse-server stop
-timeout 120 service clickhouse-server start
-
-wait_server
+stop
+start
 
 clickhouse-client --query "SHOW TABLES FROM datasets"
 clickhouse-client --query "SHOW TABLES FROM test"
@@ -56,9 +65,7 @@ clickhouse-client --query "SHOW TABLES FROM test"
 
 ./stress --output-folder test_output --skip-func-tests "$SKIP_TESTS_OPTION"
 
-timeout 120 service clickhouse-server stop
-timeout 120 service clickhouse-server start
-
-wait_server
+stop
+start
 
 clickhouse-client --query "SELECT 'Server successfuly started'" > /test_output/alive_check.txt || echo 'Server failed to start' > /test_output/alive_check.txt
diff --git a/tests/performance/linear_regression.xml b/tests/performance/linear_regression.xml
index a23924939a2..b60e890c5d9 100644
--- a/tests/performance/linear_regression.xml
+++ b/tests/performance/linear_regression.xml
@@ -1,12 +1,9 @@
 <test>
-
-
     <preconditions>
         <table_exists>test.hits</table_exists>
         <table_exists>hits_100m_single</table_exists>
     </preconditions>
 
-
     <create_query>DROP TABLE IF EXISTS test_model</create_query>
     <create_query>CREATE TABLE test_model engine = Memory as select stochasticLinearRegressionState(0.0001)(Age, Income, ParamPrice, Robotness, RefererHash) as state from test.hits</create_query>