From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
As there was a regression with the mounting of the tracefs and debugfs
file systems when tracefs_tracing_dir() and tracefs_debug_dir() were
called, add a unit test to make sure they continue to work.
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
src/tracefs-utils.c | 3 +-
utest/tracefs-utest.c | 84 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 86 insertions(+), 1 deletion(-)
diff --git a/src/tracefs-utils.c b/src/tracefs-utils.c
index d91ff40eee87..ae249de06a39 100644
--- a/src/tracefs-utils.c
+++ b/src/tracefs-utils.c
@@ -85,7 +85,8 @@ static int mount_debugfs(void)
return ret;
}
-static char *find_tracing_dir(bool debugfs, bool mount)
+/* Exported for testing purpose only */
+__hidden char *find_tracing_dir(bool debugfs, bool mount)
{
char *debug_str = NULL;
char fspath[PATH_MAX+1];
diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 010ff1d4a8fe..d1789a3d87f9 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -15,6 +15,8 @@
#include <kbuffer.h>
#include <pthread.h>
+#include <sys/mount.h>
+
#include <CUnit/CUnit.h>
#include <CUnit/Basic.h>
@@ -47,6 +49,10 @@
#define SQL_5_SQL "select end.common_pid as pid, (end.common_timestamp.usecs - start.common_timestamp.usecs) as irq_lat from irq_disable as start join irq_enable as end on start.common_pid = end.common_pid, start.parent_offs == end.parent_offs where start.common_pid != 0"
#define SQL_5_START "irq_disable"
+#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
+#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
+#define TRACEFS_DEFAULT2_PATH "/sys/kernel/debug/tracing"
+
static struct tracefs_instance *test_instance;
static struct tep_handle *test_tep;
struct test_sample {
@@ -740,6 +746,80 @@ static void test_follow_events(void)
test_instance_follow_events(test_instance);
}
+extern char *find_tracing_dir(bool debugfs, bool mount);
+static void test_mounting(void)
+{
+ const char *tracing_dir;
+ const char *debug_dir;
+ char *save_tracing = NULL;
+ char *save_debug = NULL;
+ char *dir;
+ int ret;
+
+ /* First, unmount all instances of debugfs */
+ do {
+ dir = find_tracing_dir(true, false);
+ if (dir) {
+ ret = umount(dir);
+ CU_TEST(ret == 0);
+ if (ret < 0)
+ return;
+ /* Save the first instance that's not /sys/kernel/debug */
+ if (!save_debug && strcmp(dir, DEBUGFS_DEFAULT_PATH) != 0)
+ save_debug = dir;
+ else
+ free(dir);
+ }
+ } while (dir);
+
+ /* Next, unmount all instances of tracefs */
+ do {
+ dir = find_tracing_dir(false, false);
+ if (dir) {
+ ret = umount(dir);
+ CU_TEST(ret == 0);
+ if (ret < 0)
+ return;
+ /* Save the first instance that's not in /sys/kernel/ */
+ if (!save_tracing && strncmp(dir, "/sys/kernel/", 12) != 0)
+ save_tracing = dir;
+ else
+ free(dir);
+ }
+ } while (dir);
+
+ /* Mount first the tracing dir (which should mount at /sys/kernel/tracing */
+ tracing_dir = tracefs_tracing_dir();
+ CU_TEST(tracing_dir != NULL);
+ if (tracing_dir != NULL) {
+ CU_TEST(strcmp(tracing_dir, TRACEFS_DEFAULT_PATH) == 0 ||
+ strcmp(tracing_dir, TRACEFS_DEFAULT2_PATH) == 0);
+ if (strncmp(tracing_dir, "/sys/kernel/", 12) != 0)
+ printf("Tracing directory mounted at '%s'\n",
+ tracing_dir);
+ }
+
+ /* Now mount debugfs dir, which should mount at /sys/kernel/debug */
+ debug_dir = tracefs_debug_dir();
+ CU_TEST(debug_dir != NULL);
+ if (debug_dir != NULL) {
+ CU_TEST(strcmp(debug_dir, DEBUGFS_DEFAULT_PATH) == 0);
+ if (strcmp(debug_dir, DEBUGFS_DEFAULT_PATH) != 0)
+ printf("debug directory mounted at '%s'\n",
+ debug_dir);
+ }
+
+ if (save_debug)
+ mount("debugfs", save_debug, "debugfs", 0, NULL);
+
+ if (save_tracing &&
+ (!save_debug || strncmp(save_debug, save_tracing, strlen(save_debug) != 0)))
+ mount("tracefs", save_tracing, "tracefs", 0, NULL);
+
+ free(save_debug);
+ free(save_tracing);
+}
+
static int read_trace_cpu_file(struct test_cpu_data *data)
{
unsigned long long ts;
@@ -2248,6 +2328,10 @@ void test_tracefs_lib(void)
fprintf(stderr, "Suite \"%s\" cannot be ceated\n", TRACEFS_SUITE);
return;
}
+
+ /* Must be first test */
+ CU_add_test(suite, "Test tracefs/debugfs mounting", test_mounting);
+
CU_add_test(suite, "Follow events", test_follow_events);
CU_add_test(suite, "trace cpu read",
test_trace_cpu_read);
--
2.35.1
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