@@ -46,6 +46,7 @@ int trigger_on_cpu(int cpu)
void serial_test_perf_buffer(void)
{
int err, on_len, nr_on_cpus = 0, nr_cpus, i, j;
+ int zero = 0, my_pid = getpid();
struct perf_buffer_opts pb_opts = {};
struct test_perf_buffer *skel;
cpu_set_t cpu_seen;
@@ -71,6 +72,10 @@ void serial_test_perf_buffer(void)
if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
goto out_close;
+ err = bpf_map_update_elem(bpf_map__fd(skel->maps.my_pid_map), &zero, &my_pid, 0);
+ if (!ASSERT_OK(err, "my_pid_update"))
+ goto out_close;
+
/* attach probe */
err = test_perf_buffer__attach(skel);
if (CHECK(err, "attach_kprobe", "err %d\n", err))
@@ -6,20 +6,36 @@
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __type(key, int);
+ __type(value, int);
+ __uint(max_entries, 1);
+} my_pid_map SEC(".maps");
+
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__type(key, int);
__type(value, int);
} perf_buf_map SEC(".maps");
-SEC("tp/syscalls/sys_enter_nanosleep")
+SEC("tp/raw_syscalls/sys_enter")
int handle_sys_enter(void *ctx)
{
+ int zero = 0, *my_pid, cur_pid;
int cpu = bpf_get_smp_processor_id();
+ my_pid = bpf_map_lookup_elem(&my_pid_map, &zero);
+ if (!my_pid)
+ return 1;
+
+ cur_pid = bpf_get_current_pid_tgid() >> 32;
+ if (cur_pid != *my_pid)
+ return 1;
+
bpf_perf_event_output(ctx, &perf_buf_map, BPF_F_CURRENT_CPU,
&cpu, sizeof(cpu));
- return 0;
+ return 1;
}
char _license[] SEC("license") = "GPL";
Recent change to use tp/syscalls/sys_enter_nanosleep for perf_buffer selftests causes this selftest to fail on 4.9 kernel in libbpf CI ([0]): libbpf: prog 'handle_sys_enter': failed to attach to perf_event FD 6: Invalid argument libbpf: prog 'handle_sys_enter': failed to attach to tracepoint 'syscalls/sys_enter_nanosleep': Invalid argument It's not exactly clear why, because perf_event itself is created for this tracepoint, but I can't even compile 4.9 kernel locally, so it's hard to figure this out. If anyone has better luck and would like to help investigating this, I'd really appreciate this. For now, unblock CI by switching back to raw_syscalls/sys_enter, but reduce amount of unnecessary samples emitted by filter by process ID. Use explicit ARRAY map for that to make it work on 4.9 as well, because global data isn't yet supported there. Cc: Jiri Olsa <jolsa@kernel.org> Fixes: aa274f98b269 ("selftests/bpf: Fix possible/online index mismatch in perf_buffer test") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- .../selftests/bpf/prog_tests/perf_buffer.c | 5 +++++ .../selftests/bpf/progs/test_perf_buffer.c | 20 +++++++++++++++++-- 2 files changed, 23 insertions(+), 2 deletions(-)