This is a note to let you know that I've just added the patch titled
selftests/bpf: Use read_perf_max_sample_freq() in perf_event_stackmap
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selftests-bpf-use-read_perf_max_sample_freq-in-perf_.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 396febcc5225797f3a49857f4f2f04224c9f6c4e
Author: Song Liu <song@xxxxxxxxxx>
Date: Wed Apr 12 14:04:21 2023 -0700
selftests/bpf: Use read_perf_max_sample_freq() in perf_event_stackmap
[ Upstream commit de6d014a09bf12a9a8959d60c0a1d4a41d394a89 ]
Currently, perf_event sample period in perf_event_stackmap is set too low
that the test fails randomly. Fix this by using the max sample frequency,
from read_perf_max_sample_freq().
Move read_perf_max_sample_freq() to testing_helpers.c. Replace the CHECK()
with if-printf, as CHECK is not available in testing_helpers.c.
Fixes: 1da4864c2b20 ("selftests/bpf: Add callchain_stackid")
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20230412210423.900851-2-song@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_event_stackmap.c b/tools/testing/selftests/bpf/prog_tests/perf_event_stackmap.c
index 33144c9432aeb..f4aad35afae16 100644
--- a/tools/testing/selftests/bpf/prog_tests/perf_event_stackmap.c
+++ b/tools/testing/selftests/bpf/prog_tests/perf_event_stackmap.c
@@ -63,7 +63,8 @@ void test_perf_event_stackmap(void)
PERF_SAMPLE_BRANCH_NO_FLAGS |
PERF_SAMPLE_BRANCH_NO_CYCLES |
PERF_SAMPLE_BRANCH_CALL_STACK,
- .sample_period = 5000,
+ .freq = 1,
+ .sample_freq = read_perf_max_sample_freq(),
.size = sizeof(struct perf_event_attr),
};
struct perf_event_stackmap *skel;
diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
index f4ea1a215ce4d..704f7f6c3704a 100644
--- a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
+++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
@@ -2,21 +2,6 @@
#include <test_progs.h>
#include "test_stacktrace_build_id.skel.h"
-static __u64 read_perf_max_sample_freq(void)
-{
- __u64 sample_freq = 5000; /* fallback to 5000 on error */
- FILE *f;
- __u32 duration = 0;
-
- f = fopen("/proc/sys/kernel/perf_event_max_sample_rate", "r");
- if (f == NULL)
- return sample_freq;
- CHECK(fscanf(f, "%llu", &sample_freq) != 1, "Get max sample rate",
- "return default value: 5000,err %d\n", -errno);
- fclose(f);
- return sample_freq;
-}
-
void test_stacktrace_build_id_nmi(void)
{
int control_map_fd, stackid_hmap_fd, stackmap_fd;
diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
index 9695318e8132d..9c3de39023f60 100644
--- a/tools/testing/selftests/bpf/testing_helpers.c
+++ b/tools/testing/selftests/bpf/testing_helpers.c
@@ -229,3 +229,23 @@ int bpf_test_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
return bpf_prog_load(type, NULL, license, insns, insns_cnt, &opts);
}
+
+__u64 read_perf_max_sample_freq(void)
+{
+ __u64 sample_freq = 5000; /* fallback to 5000 on error */
+ FILE *f;
+
+ f = fopen("/proc/sys/kernel/perf_event_max_sample_rate", "r");
+ if (f == NULL) {
+ printf("Failed to open /proc/sys/kernel/perf_event_max_sample_rate: err %d\n"
+ "return default value: 5000\n", -errno);
+ return sample_freq;
+ }
+ if (fscanf(f, "%llu", &sample_freq) != 1) {
+ printf("Failed to parse /proc/sys/kernel/perf_event_max_sample_rate: err %d\n"
+ "return default value: 5000\n", -errno);
+ }
+
+ fclose(f);
+ return sample_freq;
+}
diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
index 6ec00bf79cb55..eb8790f928e4c 100644
--- a/tools/testing/selftests/bpf/testing_helpers.h
+++ b/tools/testing/selftests/bpf/testing_helpers.h
@@ -20,3 +20,5 @@ struct test_filter_set;
int parse_test_list(const char *s,
struct test_filter_set *test_set,
bool is_glob_pattern);
+
+__u64 read_perf_max_sample_freq(void);
