Alexei hit following rcu warning when running prog_test -j. [ 128.049567] WARNING: suspicious RCU usage [ 128.049569] 6.1.0-rc2 #912 Tainted: G O ... [ 128.050944] kprobe_multi_link_handler+0x6c/0x1d0 [ 128.050947] ? kprobe_multi_link_handler+0x42/0x1d0 [ 128.050950] ? __cpuidle_text_start+0x8/0x8 [ 128.050952] ? __cpuidle_text_start+0x8/0x8 [ 128.050958] fprobe_handler.part.1+0xac/0x150 [ 128.050964] 0xffffffffa02130c8 [ 128.050991] ? default_idle+0x5/0x20 [ 128.050998] default_idle+0x5/0x20 It's caused by bench test attaching kprobe_multi link to default_idle function, which is not executed in rcu safe context so the kprobe handler on top of it will trigger the rcu warning. Filtering out default_idle function from the bench test. Reported-by: Alexei Starovoitov <ast@xxxxxxxxxx> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> --- tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c index d457a55ff408..b43928967515 100644 --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c @@ -358,10 +358,12 @@ static int get_syms(char ***symsp, size_t *cntp) * We attach to almost all kernel functions and some of them * will cause 'suspicious RCU usage' when fprobe is attached * to them. Filter out the current culprits - arch_cpu_idle - * and rcu_* functions. + * default_idle and rcu_* functions. */ if (!strcmp(name, "arch_cpu_idle")) continue; + if (!strcmp(name, "default_idle")) + continue; if (!strncmp(name, "rcu_", 4)) continue; if (!strcmp(name, "bpf_dispatcher_xdp_func")) -- 2.38.1
