The uprobe syscall now returns -ENXIO errno when called outside
kernel trampoline, fixing the current sigill test to reflect that
and renaming it to uprobe_error.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 .../selftests/bpf/prog_tests/uprobe_syscall.c | 34 ++++---------------
 1 file changed, 6 insertions(+), 28 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index 5da0b49eeaca..6d75ede16e7c 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -757,34 +757,12 @@ static void test_uprobe_race(void)
 #define __NR_uprobe 336
 #endif
 
-static void test_uprobe_sigill(void)
+static void test_uprobe_error(void)
 {
-	int status, err, pid;
+	long err = syscall(__NR_uprobe);
 
-	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");
+	ASSERT_EQ(err, -1, "error");
+	ASSERT_EQ(errno, ENXIO, "errno");
 }
 
 static void __test_uprobe_syscall(void)
@@ -805,8 +783,8 @@ 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();
+	if (test__start_subtest("uprobe_error"))
+		test_uprobe_error();
 	if (test__start_subtest("uprobe_regs_equal"))
 		test_uprobe_regs_equal(false);
 	if (test__start_subtest("regs_change"))
-- 
2.51.0

On Fri, Sep 5, 2025 at 1:58 PM Jiri Olsa <jolsa@kernel.org> wrote:
>
> The uprobe syscall now returns -ENXIO errno when called outside
> kernel trampoline, fixing the current sigill test to reflect that
> and renaming it to uprobe_error.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  .../selftests/bpf/prog_tests/uprobe_syscall.c | 34 ++++---------------
>  1 file changed, 6 insertions(+), 28 deletions(-)
>

Acked-by: Andrii Nakryiko <andrii@kernel.org>

> diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> index 5da0b49eeaca..6d75ede16e7c 100644
> --- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> @@ -757,34 +757,12 @@ static void test_uprobe_race(void)
>  #define __NR_uprobe 336
>  #endif
>
> -static void test_uprobe_sigill(void)
> +static void test_uprobe_error(void)
>  {
> -       int status, err, pid;
> +       long err = syscall(__NR_uprobe);
>
> -       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");
> +       ASSERT_EQ(err, -1, "error");
> +       ASSERT_EQ(errno, ENXIO, "errno");
>  }
>
>  static void __test_uprobe_syscall(void)
> @@ -805,8 +783,8 @@ 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();
> +       if (test__start_subtest("uprobe_error"))
> +               test_uprobe_error();
>         if (test__start_subtest("uprobe_regs_equal"))
>                 test_uprobe_regs_equal(false);
>         if (test__start_subtest("regs_change"))
> --
> 2.51.0
>