From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Date: Wed, 6 May 2020 00:08:34 +0000 (-0400)
Subject: testapp: gen-syscall-events: use dynamic paths provided via args
X-Git-Tag: v2.13.0-rc1~286
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=ca342eaff631d106a2c83308f19487d21cb5be40

testapp: gen-syscall-events: use dynamic paths provided via args

This is to try and mitigate the limitation found here:
https://bugs.lttng.org/issues/1261

Using an argument ensures that the path is not in the .rodata section of
the executable and reduces the chance that the kernel tracer incurs a
page fault when attempting to serialize the path argument.

The path is pre-faulted to mitigate the problem described in #1261.

Fixes #1261

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I6b6173ee5d8b33dcdf1cc391db9d1eafe00f90b9
Depends-on: lttng-ust: I5a800fc92e588c2a6a0e26282b0ad5f31c044479
---

diff --git a/tests/regression/kernel/test_callstack b/tests/regression/kernel/test_callstack
index c4a6200da..42c3fcce4 100755
--- a/tests/regression/kernel/test_callstack
+++ b/tests/regression/kernel/test_callstack
@@ -33,12 +33,15 @@ function lttng_track_pid()
 function run_workload()
 {
 	local TEST_APP=$1
+	# shift the first argument, passing along the other args if any to the
+	# test app.
+	shift
 	local start_file_sync
 	start_file_sync=$(mktemp -u)
 
 	lttng_untrack_all
 
-	./"$TEST_APP" "$start_file_sync" &
+	./"$TEST_APP" "$start_file_sync" "$@" &
 	PID=$!
 	lttng_track_pid $PID
 
@@ -108,7 +111,7 @@ function test_kernel_callstack()
 	lttng_enable_kernel_syscall_ok "$SESSION_NAME" "$EVENT_NAME" "$CHANNEL_NAME"
 	add_context_kernel_ok "$SESSION_NAME" "$CHANNEL_NAME" "callstack-kernel"
 
-	run_workload $TEST_APP_KERNELSPACE
+	run_workload "$TEST_APP_KERNELSPACE" "/proc/cpuinfo" "/proc/cmdline"
 
 	destroy_lttng_session_ok "$SESSION_NAME"
 
diff --git a/tests/regression/kernel/test_syscall b/tests/regression/kernel/test_syscall
index 9ce40dcc5..69a2bab8f 100755
--- a/tests/regression/kernel/test_syscall
+++ b/tests/regression/kernel/test_syscall
@@ -27,7 +27,7 @@ function trace_testapp()
 	lttng_untrack_kernel_all_ok
 
 	# Launch the testapp and save its Process ID
-	./"$TESTCMD" "$start_file_sync" &
+	./"$TESTCMD" "$start_file_sync" "/proc/cpuinfo" "/proc/cmdline" &
 	PID=$!
 
 	# Set LTTng to track this PID and start the tracing
diff --git a/tests/utils/testapp/gen-syscall-events/gen-syscall-events.c b/tests/utils/testapp/gen-syscall-events/gen-syscall-events.c
index 1ec29139e..9ab650933 100644
--- a/tests/utils/testapp/gen-syscall-events/gen-syscall-events.c
+++ b/tests/utils/testapp/gen-syscall-events/gen-syscall-events.c
@@ -88,16 +88,19 @@ error:
 int main(int argc, char **argv)
 {
 	int ret;
-	char *start_file;
+	const char *start_file, *path1, *path2;
 
-	if (argc != 2) {
+	if (argc != 4) {
 		fprintf(stderr, "Error: Missing argument\n");
+		fprintf(stderr, "USAGE: %s PATH_WAIT_FILE PATH1_TO_OPEN PATH2_TO_OPEN\n", argv[0]);
 		fprintf(stderr, "USAGE: %s PATH_WAIT_FILE\n", argv[0]);
 		ret = -1;
 		goto error;
 	}
 
 	start_file = argv[1];
+	path1 = argv[2];
+	path2 = argv[3];
 
 	/*
 	 * Wait for the start_file to be created by an external process
@@ -112,13 +115,13 @@ int main(int argc, char **argv)
 	 * Start generating syscalls. We use syscall(2) to prevent libc to change
 	 * the underlying syscall. e.g. calling openat(2) instead of open(2).
 	 */
-	ret = open_read_close("/proc/cpuinfo");
+	ret = open_read_close(path1);
 	if (ret == -1) {
 		ret = -1;
 		goto error;
 	}
 
-	ret = open_read_close("/proc/cmdline");
+	ret = open_read_close(path2);
 	if (ret == -1) {
 		ret = -1;
 		goto error;