From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Date: Tue, 15 Oct 2019 20:50:46 +0000 (-0400)
Subject: Tests: use "kill -0" for app existence check in NS tests
X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=commitdiff_plain;h=70a7f9f74ac7fc5717056ff083eb7df905a056af

Tests: use "kill -0" for app existence check in NS tests

Removing the sleep 0.5 we hit a race where the "-f /proc/$pid_app"
test returns false immediately. Using "kill -0" protects us against
such races. From kill (2):

If sig is 0, then no signal is sent, but existence and permission
checks are still performed; this can be used to check for the
existence of a process ID or process group ID that the caller is
permitted to signal.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/tests/regression/kernel/test_ns_contexts_change b/tests/regression/kernel/test_ns_contexts_change
index 905f6cf2b..08150244d 100755
--- a/tests/regression/kernel/test_ns_contexts_change
+++ b/tests/regression/kernel/test_ns_contexts_change
@@ -119,13 +119,11 @@ function test_ns()
 
 		touch "$file_sync_wait_before_unshare"
 
-		# Let the app do it's thing before entering the synchronisation loop
-		sleep 0.5
-
 		while [ ! -f "$file_sync_signal_after_unshare" ]; do
 			# Break if the app failed / died
-			if [ ! -f "/proc/$app_pid" ]; then
+			if ! kill -0 "$app_pid" ; then
 				break
+				echo "# App failed"
 			fi
 			echo "# Waiting for app..."
 			sleep 0.5
diff --git a/tests/regression/ust/namespaces/test_ns_contexts_change b/tests/regression/ust/namespaces/test_ns_contexts_change
index 18a22e588..0e03d5393 100755
--- a/tests/regression/ust/namespaces/test_ns_contexts_change
+++ b/tests/regression/ust/namespaces/test_ns_contexts_change
@@ -72,12 +72,10 @@ function test_ns()
 	$TESTAPP_BIN -n "$ns" -i $NUM_EVENT -a "$file_sync_after_unshare" -b "$file_sync_before_last" &
 	app_pid=$!
 
-	# Let the app do it's thing before entering the synchronisation loop
-	sleep 0.5
-
 	while [ ! -f "$file_sync_after_unshare" ]; do
 		# Break if the app failed / died
-		if [ ! -f "/proc/$app_pid" ]; then
+		if ! kill -0 "$app_pid" ; then
+			echo "# App failed"
 			break
 		fi
 		echo "# Waiting for app..."