On Mon, Jan 11, 2021 at 10:20 AM Qais Yousef <qais.yousef@xxxxxxx> wrote: > > Reuse module_attach infrastructure to add a new bare tracepoint to check > we can attach to it as a raw tracepoint. > > Signed-off-by: Qais Yousef <qais.yousef@xxxxxxx> > --- > > Andrii > > I was getting the error below when I was trying to run the test. > I had to comment out all related fentry* code to be able to test the raw_tp > stuff. Not sure something I've done wrong or it's broken for some reason. > I was on v5.11-rc2. Check that you have all the required Kconfig options from tools/testing/selftests/bpf/config. And also you will need to build pahole from master, 1.19 doesn't have some fixes that add kernel module support. I think pahole is the reasons why you have the failure below. > > $ sudo ./test_progs -v -t module_attach use -vv when debugging stuff like that with test_progs, it will output libbpf detailed logs, that often are very helpful > bpf_testmod.ko is already unloaded. > Loading bpf_testmod.ko... > Successfully loaded bpf_testmod.ko. > test_module_attach:PASS:skel_open 0 nsec > test_module_attach:PASS:set_attach_target 0 nsec > test_module_attach:PASS:skel_load 0 nsec > libbpf: prog 'handle_fentry': failed to attach: ERROR: strerror_r(-524)=22 > libbpf: failed to auto-attach program 'handle_fentry': -524 > test_module_attach:FAIL:skel_attach skeleton attach failed: -524 > #58 module_attach:FAIL > Successfully unloaded bpf_testmod.ko. > Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED > But even apart from test failure, there seems to be kernel build failure. See [0] for what fails in kernel-patches CI. [0] https://travis-ci.com/github/kernel-patches/bpf/builds/212730017 > > .../selftests/bpf/bpf_testmod/bpf_testmod-events.h | 6 ++++++ > tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 2 ++ > tools/testing/selftests/bpf/prog_tests/module_attach.c | 1 + > tools/testing/selftests/bpf/progs/test_module_attach.c | 10 ++++++++++ > 4 files changed, 19 insertions(+) > > diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h > index b83ea448bc79..e1ada753f10c 100644 > --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h > +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h > @@ -28,6 +28,12 @@ TRACE_EVENT(bpf_testmod_test_read, > __entry->pid, __entry->comm, __entry->off, __entry->len) > ); > > +/* A bare tracepoint with no event associated with it */ > +DECLARE_TRACE(bpf_testmod_test_read_bare, > + TP_PROTO(struct task_struct *task, struct bpf_testmod_test_read_ctx *ctx), > + TP_ARGS(task, ctx) > +); > + > #endif /* _BPF_TESTMOD_EVENTS_H */ > > #undef TRACE_INCLUDE_PATH > diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c > index 2df19d73ca49..d63cebdaca44 100644 > --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c > +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c > @@ -22,6 +22,8 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj, > }; > > trace_bpf_testmod_test_read(current, &ctx); > + ctx.len++; > + trace_bpf_testmod_test_read_bare(current, &ctx); It's kind of boring to have two read tracepoints :) Do you mind adding a write tracepoint and use bare tracepoint there? You won't need this ctx.len++ hack as well. Feel free to add identical bpf_testmod_test_write_ctx (renaming it is more of a pain). > > return -EIO; /* always fail */ > } > diff --git a/tools/testing/selftests/bpf/prog_tests/module_attach.c b/tools/testing/selftests/bpf/prog_tests/module_attach.c > index 50796b651f72..7085a118f38c 100644 > --- a/tools/testing/selftests/bpf/prog_tests/module_attach.c > +++ b/tools/testing/selftests/bpf/prog_tests/module_attach.c > @@ -50,6 +50,7 @@ void test_module_attach(void) > ASSERT_OK(trigger_module_test_read(READ_SZ), "trigger_read"); > > ASSERT_EQ(bss->raw_tp_read_sz, READ_SZ, "raw_tp"); > + ASSERT_EQ(bss->raw_tp_bare_read_sz, READ_SZ+1, "raw_tp_bare"); > ASSERT_EQ(bss->tp_btf_read_sz, READ_SZ, "tp_btf"); > ASSERT_EQ(bss->fentry_read_sz, READ_SZ, "fentry"); > ASSERT_EQ(bss->fentry_manual_read_sz, READ_SZ, "fentry_manual"); > diff --git a/tools/testing/selftests/bpf/progs/test_module_attach.c b/tools/testing/selftests/bpf/progs/test_module_attach.c > index efd1e287ac17..08aa157afa1d 100644 > --- a/tools/testing/selftests/bpf/progs/test_module_attach.c > +++ b/tools/testing/selftests/bpf/progs/test_module_attach.c > @@ -17,6 +17,16 @@ int BPF_PROG(handle_raw_tp, > return 0; > } > > +__u32 raw_tp_bare_read_sz = 0; > + > +SEC("raw_tp/bpf_testmod_test_read_bare") > +int BPF_PROG(handle_raw_tp_bare, > + struct task_struct *task, struct bpf_testmod_test_read_ctx *read_ctx) > +{ > + raw_tp_bare_read_sz = BPF_CORE_READ(read_ctx, len); > + return 0; > +} > + > __u32 tp_btf_read_sz = 0; > > SEC("tp_btf/bpf_testmod_test_read") > -- > 2.25.1 >
