2023-05-20 00:02:22

by Song Liu

Subject: [PATCH] perf: separate bpf_counter_list and bpf_filters

evsel uses a union for the two lists. This turned out to be error prone.
For example:

[root@quaco ~]# perf stat --bpf-prog 5246
Error: cpu-clock event does not have sample flags 66c660
failed to set filter "(null)" on event cpu-clock with 2 (No such file or
directory)

Fix this issue by separating the two lists.

Fixes: 56ec9457a4a2 ("perf bpf filter: Implement event sample filtering")
Signed-off-by: Song Liu <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
---
tools/perf/util/evsel.c | 1 +
tools/perf/util/evsel.h | 6 ++----
2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 2f5910b31fa9..c2dbb5647e75 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -282,6 +282,7 @@ void evsel__init(struct evsel *evsel,
evsel->bpf_fd = -1;
INIT_LIST_HEAD(&evsel->config_terms);
INIT_LIST_HEAD(&evsel->bpf_counter_list);
+ INIT_LIST_HEAD(&evsel->bpf_filters);
perf_evsel__object.init(evsel);
evsel->sample_size = __evsel__sample_size(attr->sample_type);
evsel__calc_id_pos(evsel);
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index df8928745fc6..0f54f28a69c2 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -151,10 +151,8 @@ struct evsel {
*/
struct bpf_counter_ops *bpf_counter_ops;

- union {
- struct list_head bpf_counter_list; /* for perf-stat -b */
- struct list_head bpf_filters; /* for perf-record --filter */
- };
+ struct list_head bpf_counter_list; /* for perf-stat -b */
+ struct list_head bpf_filters; /* for perf-record --filter */

/* for perf-stat --use-bpf */
int bperf_leader_prog_fd;
--
2.34.1

2023-05-26 19:24:13

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH] perf: separate bpf_counter_list and bpf_filters

Em Fri, May 19, 2023 at 04:57:57PM -0700, Song Liu escreveu:
> evsel uses a union for the two lists. This turned out to be error prone.
> For example:
>
> [root@quaco ~]# perf stat --bpf-prog 5246
> Error: cpu-clock event does not have sample flags 66c660
> failed to set filter "(null)" on event cpu-clock with 2 (No such file or
> directory)
>
> Fix this issue by separating the two lists.


Thanks, applied.

- Arnaldo


> Fixes: 56ec9457a4a2 ("perf bpf filter: Implement event sample filtering")
> Signed-off-by: Song Liu <[email protected]>
> Acked-by: Namhyung Kim <[email protected]>
> ---
> tools/perf/util/evsel.c | 1 +
> tools/perf/util/evsel.h | 6 ++----
> 2 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 2f5910b31fa9..c2dbb5647e75 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -282,6 +282,7 @@ void evsel__init(struct evsel *evsel,
> evsel->bpf_fd = -1;
> INIT_LIST_HEAD(&evsel->config_terms);
> INIT_LIST_HEAD(&evsel->bpf_counter_list);
> + INIT_LIST_HEAD(&evsel->bpf_filters);
> perf_evsel__object.init(evsel);
> evsel->sample_size = __evsel__sample_size(attr->sample_type);
> evsel__calc_id_pos(evsel);
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index df8928745fc6..0f54f28a69c2 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -151,10 +151,8 @@ struct evsel {
> */
> struct bpf_counter_ops *bpf_counter_ops;
>
> - union {
> - struct list_head bpf_counter_list; /* for perf-stat -b */
> - struct list_head bpf_filters; /* for perf-record --filter */
> - };
> + struct list_head bpf_counter_list; /* for perf-stat -b */
> + struct list_head bpf_filters; /* for perf-record --filter */
>
> /* for perf-stat --use-bpf */
> int bperf_leader_prog_fd;
> --
> 2.34.1
>

--

- Arnaldo