[RFC PATCH 7/8] selftests/bpf: Add test for uprobe prologue optimization
From: Jiri Olsa <jolsa@kernel.org>
Date: 2025-11-17 12:42:27
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, Linus Torvalds
Adding test that places uprobe on top of supported prologue and checks that the uprobe gets properly optimized. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- .../selftests/bpf/prog_tests/uprobe_syscall.c | 63 ++++++++++++++++--- 1 file changed, 53 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index 27fa6f309188..c6a58afc7ace 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c@@ -428,21 +428,21 @@ static void *check_attach(struct uprobe_syscall_executed *skel, trigger_t trigge return tramp; } -static void check_detach(void *addr, void *tramp) +static void check_detach(void *addr, void *tramp, unsigned char *orig) { /* [uprobes_trampoline] stays after detach */ ASSERT_OK(find_uprobes_trampoline(tramp), "uprobes_trampoline"); - ASSERT_OK(memcmp(addr, nop5, 5), "nop5"); + ASSERT_OK(memcmp(addr, orig, 5), "orig"); } static void check(struct uprobe_syscall_executed *skel, struct bpf_link *link, - trigger_t trigger, void *addr, int executed) + trigger_t trigger, void *addr, int executed, unsigned char *orig) { void *tramp; tramp = check_attach(skel, trigger, addr, executed); bpf_link__destroy(link); - check_detach(addr, tramp); + check_detach(addr, tramp, orig); } static void test_uprobe_legacy(void)
@@ -470,7 +470,7 @@ static void test_uprobe_legacy(void) if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts")) goto cleanup; - check(skel, link, uprobe_test, uprobe_test, 2); + check(skel, link, uprobe_test, uprobe_test, 2, nop5); /* uretprobe */ skel->bss->executed = 0;
@@ -480,7 +480,7 @@ static void test_uprobe_legacy(void) if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts")) goto cleanup; - check(skel, link, uprobe_test, uprobe_test, 2); + check(skel, link, uprobe_test, uprobe_test, 2, nop5); cleanup: uprobe_syscall_executed__destroy(skel);
@@ -512,7 +512,7 @@ static void test_uprobe_multi(void) if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi")) goto cleanup; - check(skel, link, uprobe_test, uprobe_test, 2); + check(skel, link, uprobe_test, uprobe_test, 2, nop5); /* uretprobe.multi */ skel->bss->executed = 0;
@@ -522,7 +522,7 @@ static void test_uprobe_multi(void) if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi")) goto cleanup; - check(skel, link, uprobe_test, uprobe_test, 2); + check(skel, link, uprobe_test, uprobe_test, 2, nop5); cleanup: uprobe_syscall_executed__destroy(skel);
@@ -555,7 +555,7 @@ static void test_uprobe_session(void) if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi")) goto cleanup; - check(skel, link, uprobe_test, uprobe_test, 4); + check(skel, link, uprobe_test, uprobe_test, 4, nop5); cleanup: uprobe_syscall_executed__destroy(skel);
@@ -584,7 +584,7 @@ static void test_uprobe_usdt(void) if (!ASSERT_OK_PTR(link, "bpf_program__attach_usdt")) goto cleanup; - check(skel, link, usdt_test, addr, 2); + check(skel, link, usdt_test, addr, 2, nop5); cleanup: uprobe_syscall_executed__destroy(skel);
@@ -813,6 +813,47 @@ static void test_emulate(void) uprobe_syscall__destroy(skel); } +__attribute__((aligned(16))) +__nocf_check __weak __naked void prologue_trigger(void) +{ + asm volatile ( + "pushq %rbp\n" + "movq %rsp,%rbp\n" + "subq $0xb0,%rsp\n" + "addq $0xb0,%rsp\n" + "pop %rbp\n" + "ret\n" + ); +} + +static void test_optimize_prologue(void) +{ + struct uprobe_syscall_executed *skel = NULL; + struct bpf_link *link; + unsigned long offset; + + offset = get_uprobe_offset(&prologue_trigger); + if (!ASSERT_GE(offset, 0, "get_uprobe_offset")) + goto cleanup; + + /* uprobe */ + skel = uprobe_syscall_executed__open_and_load(); + if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load")) + return; + + skel->bss->pid = getpid(); + + link = bpf_program__attach_uprobe_opts(skel->progs.test_uprobe, + 0, "/proc/self/exe", offset, NULL); + if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts")) + goto cleanup; + + check(skel, link, prologue_trigger, prologue_trigger, 2, (unsigned char *) prologue_trigger); + +cleanup: + uprobe_syscall_executed__destroy(skel); +} + static void __test_uprobe_syscall(void) { if (test__start_subtest("uretprobe_regs_equal"))
@@ -839,6 +880,8 @@ static void __test_uprobe_syscall(void) test_regs_change(); if (test__start_subtest("emulate_mov")) test_emulate(); + if (test__start_subtest("optimize_prologue")) + test_optimize_prologue(); } #else static void __test_uprobe_syscall(void)
--
2.51.1