On Fri, Nov 27, 2020 at 02:43:56PM +0900, Namhyung Kim wrote:
> It didn't check the tool->cgroup_events bit which is set when
> the --all-cgroups option is given. Without it, samples will not have
> cgroup info so no reason to synthesize.
>
> We can check the PERF_RECORD_CGROUP records after running perf record
> *WITHOUT* the --all-cgroups option:
>
> Before:
> $ perf report -D | grep CGROUP
> 0 0 0x8430 [0x38]: PERF_RECORD_CGROUP cgroup: 1 /
> CGROUP events: 1
> CGROUP events: 0
> CGROUP events: 0
>
> After:
> $ perf report -D | grep CGROUP
> CGROUP events: 0
> CGROUP events: 0
> CGROUP events: 0
>
> Fixes: 8fb4b67939e16 ("perf record: Add --all-cgroups option")
> Signed-off-by: Namhyung Kim <[email protected]>
> ---
> tools/perf/util/synthetic-events.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/tools/perf/util/synthetic-events.c
> b/tools/perf/util/synthetic-events.c
> index 8a23391558cf..d9c624377da7 100644
> --- a/tools/perf/util/synthetic-events.c
> +++ b/tools/perf/util/synthetic-events.c
> @@ -563,6 +563,9 @@ int perf_event__synthesize_cgroups(struct perf_tool *tool,
> char cgrp_root[PATH_MAX];
> size_t mount_len; /* length of mount point in the path */
>
> + if (!tool || !tool->cgroup_events)
> + return 0;
can !tool actually happen here? or it's just being extra cautious
Acked-by: Jiri Olsa <[email protected]>
thanks,
jirka
> +
> if (cgroupfs_find_mountpoint(cgrp_root, PATH_MAX, "perf_event") < 0) {
> pr_debug("cannot find cgroup mount point\n");
> return -1;
> --
> 2.29.2.454.gaff20da3a2-goog
>
