[PATCHv4 bpf-next 6/6] selftests/bpf: Add kprobe multi write ctx attach test
From: Jiri Olsa <jolsa@kernel.org>
Date: 2025-09-16 21:54:24
Also in:
bpf, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Shuah Khan, Linus Torvalds
Adding test to check we can't attach kprobe multi program that writes to the context. It's x86_64 specific test. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- .../bpf/prog_tests/kprobe_multi_test.c | 27 +++++++++++++++++++ .../selftests/bpf/progs/kprobe_write_ctx.c | 7 +++++ 2 files changed, 34 insertions(+)
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 171706e78da8..6cfaa978bc9a 100644
--- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c@@ -7,6 +7,7 @@ #include "kprobe_multi_session.skel.h" #include "kprobe_multi_session_cookie.skel.h" #include "kprobe_multi_verifier.skel.h" +#include "kprobe_write_ctx.skel.h" #include "bpf/libbpf_internal.h" #include "bpf/hashmap.h"
@@ -539,6 +540,30 @@ static void test_attach_override(void) kprobe_multi_override__destroy(skel); } +#ifdef __x86_64__ +static void test_attach_write_ctx(void) +{ + struct kprobe_write_ctx *skel = NULL; + struct bpf_link *link = NULL; + + skel = kprobe_write_ctx__open_and_load(); + if (!ASSERT_OK_PTR(skel, "kprobe_write_ctx__open_and_load")) + return; + + link = bpf_program__attach_kprobe_opts(skel->progs.kprobe_multi_write_ctx, + "bpf_fentry_test1", NULL); + if (!ASSERT_ERR_PTR(link, "bpf_program__attach_kprobe_opts")) + bpf_link__destroy(link); + + kprobe_write_ctx__destroy(skel); +} +#else +static void test_attach_write_ctx(void) +{ + test__skip(); +} +#endif + void serial_test_kprobe_multi_bench_attach(void) { if (test__start_subtest("kernel"))
@@ -578,5 +603,7 @@ void test_kprobe_multi_test(void) test_session_cookie_skel_api(); if (test__start_subtest("unique_match")) test_unique_match(); + if (test__start_subtest("attach_write_ctx")) + test_attach_write_ctx(); RUN_TESTS(kprobe_multi_verifier); }
diff --git a/tools/testing/selftests/bpf/progs/kprobe_write_ctx.c b/tools/testing/selftests/bpf/progs/kprobe_write_ctx.c
index 4621a5bef4e2..f77aef0474d3 100644
--- a/tools/testing/selftests/bpf/progs/kprobe_write_ctx.c
+++ b/tools/testing/selftests/bpf/progs/kprobe_write_ctx.c@@ -12,4 +12,11 @@ int kprobe_write_ctx(struct pt_regs *ctx) ctx->ax = 0; return 0; } + +SEC("kprobe.multi") +int kprobe_multi_write_ctx(struct pt_regs *ctx) +{ + ctx->ax = 0; + return 0; +} #endif
--
2.51.0