Depending of the kernel configuration, some ftrace files are optional
and may not exist. This should not confuse trace-cmd, as it is a valid
case. One such case is tracing_max_latency file, when CONFIG_TRACER_MAX_TRACE
or CONFIG_HWLAT_TRACER are not set.
A check is added in write_instance_file() to ensure the file exist before trying
to write in it.
https://bugzilla.kernel.org/show_bug.cgi?id=205241
Reported-by: Valentin Schneider <valentin.schneider@xxxxxxx>
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
tracecmd/trace-record.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 81aca1f..c65731f 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -813,11 +813,14 @@ static int
write_instance_file(struct buffer_instance *instance,
const char *file, const char *str, const char *type)
{
+ struct stat st;
char *path;
int ret;
path = get_instance_file(instance, file);
- ret = write_file(path, str, type);
+ ret = stat(path, &st);
+ if (ret == 0)
+ ret = write_file(path, str, type);
tracecmd_put_tracing_file(path);
return ret;
--
2.21.0
|