Hi Tzvetomir,
On 18/10/2019 15:57, Tzvetomir Stoyanov (VMware) wrote:
> 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>
Ran through my test just fine, so:
Tested-by: Valentin Schneider <valentin.schneider@xxxxxxx>
Thanks for looking at this!
> ---
> 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;
>
|