diff options
| author | Andrii Nakryiko <andrii@kernel.org> | 2021-09-22 00:00:34 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-09-22 05:40:09 +0300 |
| commit | d3b0e3b03cf75896de7b03ad1fca2bff98c59f15 (patch) | |
| tree | b4044bc128e8efacb2420cfc4b5fe4e8c63a61f2 | |
| parent | 303a257223a3bbd7cc6ccc2b7777179c8d9f3989 (diff) | |
| download | linux-d3b0e3b03cf75896de7b03ad1fca2bff98c59f15.tar.xz | |
selftests/bpf: Adopt attach_probe selftest to work on old kernels
Make sure to not use ref_ctr_off feature when running on old kernels
that don't support this feature. This allows to test libbpf's legacy
kprobe and uprobe logic on old kernels.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210921210036.1545557-3-andrii@kernel.org
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/attach_probe.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c index bf307bb9e446..6c511dcd1465 100644 --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c @@ -14,6 +14,20 @@ void test_attach_probe(void) struct test_attach_probe* skel; size_t uprobe_offset; ssize_t base_addr, ref_ctr_offset; + bool legacy; + + /* Check if new-style kprobe/uprobe API is supported. + * Kernels that support new FD-based kprobe and uprobe BPF attachment + * through perf_event_open() syscall expose + * /sys/bus/event_source/devices/kprobe/type and + * /sys/bus/event_source/devices/uprobe/type files, respectively. They + * contain magic numbers that are passed as "type" field of + * perf_event_attr. Lack of such file in the system indicates legacy + * kernel with old-style kprobe/uprobe attach interface through + * creating per-probe event through tracefs. For such cases + * ref_ctr_offset feature is not supported, so we don't test it. + */ + legacy = access("/sys/bus/event_source/devices/kprobe/type", F_OK) != 0; base_addr = get_base_addr(); if (CHECK(base_addr < 0, "get_base_addr", @@ -45,10 +59,11 @@ void test_attach_probe(void) goto cleanup; skel->links.handle_kretprobe = kretprobe_link; - ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before"); + if (!legacy) + ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before"); uprobe_opts.retprobe = false; - uprobe_opts.ref_ctr_offset = ref_ctr_offset; + uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset; uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe, 0 /* self pid */, "/proc/self/exe", @@ -58,11 +73,12 @@ void test_attach_probe(void) goto cleanup; skel->links.handle_uprobe = uprobe_link; - ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after"); + if (!legacy) + ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after"); /* if uprobe uses ref_ctr, uretprobe has to use ref_ctr as well */ uprobe_opts.retprobe = true; - uprobe_opts.ref_ctr_offset = ref_ctr_offset; + uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset; uretprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe, -1 /* any pid */, "/proc/self/exe", |