[PATCHv6 perf/core 16/22] selftests/bpf: Add uprobe syscall sigill signal test

[Jiri Olsa <jolsa@kernel.org>]

Make sure that calling uprobe syscall from outside uprobe trampoline
results in sigill signal.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 .../selftests/bpf/prog_tests/uprobe_syscall.c | 36 +++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index 3d27c8bc019e..02e98cba5cc6 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -735,6 +735,40 @@ static void test_uprobe_race(void)
 	ASSERT_FALSE(USDT_SEMA_IS_ACTIVE(race), "race_semaphore");
 }
 
+#ifndef __NR_uprobe
+#define __NR_uprobe 336
+#endif
+
+static void test_uprobe_sigill(void)
+{
+	int status, err, pid;
+
+	pid = fork();
+	if (!ASSERT_GE(pid, 0, "fork"))
+		return;
+	/* child */
+	if (pid == 0) {
+		asm volatile (
+			"pushq %rax\n"
+			"pushq %rcx\n"
+			"pushq %r11\n"
+			"movq $" __stringify(__NR_uprobe) ", %rax\n"
+			"syscall\n"
+			"popq %r11\n"
+			"popq %rcx\n"
+			"retq\n"
+		);
+		exit(0);
+	}
+
+	err = waitpid(pid, &status, 0);
+	ASSERT_EQ(err, pid, "waitpid");
+
+	/* verify the child got killed with SIGILL */
+	ASSERT_EQ(WIFSIGNALED(status), 1, "WIFSIGNALED");
+	ASSERT_EQ(WTERMSIG(status), SIGILL, "WTERMSIG");
+}
+
 static void __test_uprobe_syscall(void)
 {
 	if (test__start_subtest("uretprobe_regs_equal"))
@@ -755,6 +789,8 @@ static void __test_uprobe_syscall(void)
 		test_uprobe_usdt();
 	if (test__start_subtest("uprobe_race"))
 		test_uprobe_race();
+	if (test__start_subtest("uprobe_sigill"))
+		test_uprobe_sigill();
 }
 #else
 static void __test_uprobe_syscall(void)
-- 
2.50.1