Re: [PATCH bpf-next v2 2/3] selftests/bpf: skip recursive functions for kprobe_multi

Indeed, it is so long. Sir Dong, of Meng.

On Tue, Aug 26, 2025 at 4:05 AM Menglong Dong menglong8.dong@gmail.com wrote:

Some functions is recursive for the kprobe_multi and impact the benchmark results. So just skip them.

Signed-off-by: Menglong Dong dongml2@chinatelecom.cn

v2:

• introduce trace_blacklist instead of copy-pasting strcmp

---

tools/testing/selftests/bpf/trace_helpers.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)

diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index d24baf244d1f..9577979bd84d 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -19,6 +19,7 @@ #include <gelf.h> #include "bpf/hashmap.h" #include "bpf/libbpf_internal.h" +#include "bpf_util.h"

#define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" #define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" @@ -540,8 +541,20 @@ static bool is_invalid_entry(char *buf, bool kernel) return false; }

+static const char * const trace_blacklist[] = {

•   "migrate_disable",
  

•   "migrate_enable",
  

•   "rcu_read_unlock_strict",
  

•   "preempt_count_add",
  

•   "preempt_count_sub",
  

•   "__rcu_read_lock",
  

•   "__rcu_read_unlock",
  

+};

static bool skip_entry(char *name) {

•   int i;
  

•   /*
     * We attach to almost all kernel functions and some of them
     * will cause 'suspicious RCU usage' when fprobe is attached
  

@@ -559,6 +572,12 @@ static bool skip_entry(char *name) if (!strncmp(name, "__ftrace_invalid_address__", sizeof("__ftrace_invalid_address__") - 1)) return true;

•   for (i = 0; i < ARRAY_SIZE(trace_blacklist); i++) {
  

•           if (!strcmp(name, trace_blacklist[i]))
  

•                   return true;
  

•   }
  

•   return false;
  

}

-- 2.51.0