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Message-ID: <20250801210238.2207429-5-jolsa@kernel.org>
Date: Fri, 1 Aug 2025 23:02:38 +0200
From: Jiri Olsa <jolsa@...nel.org>
To: Oleg Nesterov <oleg@...hat.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Andrii Nakryiko <andrii@...nel.org>
Cc: bpf@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-trace-kernel@...r.kernel.org,
x86@...nel.org,
Song Liu <songliubraving@...com>,
Yonghong Song <yhs@...com>,
John Fastabend <john.fastabend@...il.com>,
Hao Luo <haoluo@...gle.com>,
Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...nel.org>
Subject: [RFC 4/4] selftests/bpf: Add uprobe context ip register change test
Adding test to check we can change the application execution
through instruction pointer change through uprobe program.
It's x86_64 specific test.
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
.../testing/selftests/bpf/prog_tests/uprobe.c | 48 +++++++++++++++++++
.../testing/selftests/bpf/progs/test_uprobe.c | 14 ++++++
2 files changed, 62 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe.c b/tools/testing/selftests/bpf/prog_tests/uprobe.c
index 7c7cb08d10b3..05cd3b65260f 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe.c
@@ -190,10 +190,58 @@ static void regs_common(void)
test_uprobe__destroy(skel);
}
+static __naked unsigned long uprobe_regs_change_ip_1(void)
+{
+ asm volatile (
+ "movq $0xc0ffee, %rax\n"
+ "ret\n"
+ );
+}
+
+static __naked unsigned long uprobe_regs_change_ip_2(void)
+{
+ asm volatile (
+ "movq $0xdeadbeef, %rax\n"
+ "ret\n"
+ );
+}
+
+static void regs_ip(void)
+{
+ LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
+ struct test_uprobe *skel;
+ unsigned long ret;
+
+ skel = test_uprobe__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ skel->bss->my_pid = getpid();
+ skel->bss->ip = (unsigned long) uprobe_regs_change_ip_2;
+
+ uprobe_opts.func_name = "uprobe_regs_change_ip_1";
+ skel->links.test_regs_change_ip = bpf_program__attach_uprobe_opts(
+ skel->progs.test_regs_change_ip,
+ -1,
+ "/proc/self/exe",
+ 0 /* offset */,
+ &uprobe_opts);
+ if (!ASSERT_OK_PTR(skel->links.test_regs_change_ip, "bpf_program__attach_uprobe_opts"))
+ goto cleanup;
+
+ ret = uprobe_regs_change_ip_1();
+ ASSERT_EQ(ret, 0xdeadbeef, "ret");
+
+cleanup:
+ test_uprobe__destroy(skel);
+}
+
static void test_uprobe_regs_change(void)
{
if (test__start_subtest("regs_change_common"))
regs_common();
+ if (test__start_subtest("regs_change_ip"))
+ regs_ip();
}
#else
static void test_uprobe_regs_change(void) { }
diff --git a/tools/testing/selftests/bpf/progs/test_uprobe.c b/tools/testing/selftests/bpf/progs/test_uprobe.c
index 9437bd76a437..12f4065fca20 100644
--- a/tools/testing/selftests/bpf/progs/test_uprobe.c
+++ b/tools/testing/selftests/bpf/progs/test_uprobe.c
@@ -82,4 +82,18 @@ int BPF_UPROBE(test_regs_change)
ctx->si = regs.si;
return 0;
}
+
+unsigned long ip;
+
+SEC("uprobe")
+int BPF_UPROBE(test_regs_change_ip)
+{
+ pid_t pid = bpf_get_current_pid_tgid() >> 32;
+
+ if (pid != my_pid)
+ return 0;
+
+ ctx->ip = ip;
+ return 0;
+}
#endif
--
2.50.1
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