From: Namhyung Kim namhyung@kernel.org
[ Upstream commit 3da35231d9e4949c4ae40e3ce653e7c468455d55 ]
The previous cpu map introduced a bug in the bperf cgroup counter. This results in a failure when user gives a partial cpu map starting from non-zero.
$ sudo ./perf stat -C 1-2 --bpf-counters --for-each-cgroup ^. sleep 1 libbpf: prog 'on_cgrp_switch': failed to create BPF link for perf_event FD 0: -9 (Bad file descriptor) Failed to attach cgroup program
To get the FD of an evsel, it should use a map index not the CPU number.
Fixes: 0255571a16059c8e ("perf cpumap: Switch to using perf_cpu_map API") Signed-off-by: Namhyung Kim namhyung@kernel.org Cc: Adrian Hunter adrian.hunter@intel.com Cc: bpf@vger.kernel.org Cc: Ian Rogers irogers@google.com Cc: Ingo Molnar mingo@kernel.org Cc: Jiri Olsa jolsa@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Song Liu songliubraving@fb.com Link: https://lore.kernel.org/r/20220916184132.1161506-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/bpf_counter_cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/bpf_counter_cgroup.c b/tools/perf/util/bpf_counter_cgroup.c index 63b9db657442..97c69a249c6e 100644 --- a/tools/perf/util/bpf_counter_cgroup.c +++ b/tools/perf/util/bpf_counter_cgroup.c @@ -95,7 +95,7 @@ static int bperf_load_program(struct evlist *evlist)
perf_cpu_map__for_each_cpu(cpu, i, evlist->core.all_cpus) { link = bpf_program__attach_perf_event(skel->progs.on_cgrp_switch, - FD(cgrp_switch, cpu.cpu)); + FD(cgrp_switch, i)); if (IS_ERR(link)) { pr_err("Failed to attach cgroup program\n"); err = PTR_ERR(link); @@ -123,7 +123,7 @@ static int bperf_load_program(struct evlist *evlist)
map_fd = bpf_map__fd(skel->maps.events); perf_cpu_map__for_each_cpu(cpu, j, evlist->core.all_cpus) { - int fd = FD(evsel, cpu.cpu); + int fd = FD(evsel, j); __u32 idx = evsel->core.idx * total_cpus + cpu.cpu;
err = bpf_map_update_elem(map_fd, &idx, &fd,