bpf: Count stats for kprobe_multi programs

Adding support to gather missed stats for kprobe_multi
programs due to bpf_prog_active protection.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Song Liu <song@kernel.org>
Reviewed-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20230920213145.1941596-2-jolsa@kernel.org

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 868008f56fec24fe7030d2fed9b063d1e1dd7926..54827d04c9a67394e3f69d1bd182357a97c3cd3b 100644 (file)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2710,6 +2710,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
        int err;
 
        if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
+               bpf_prog_inc_misses_counter(link->link.prog);
                err = 0;
                goto out;
        }