selftests/user_events: Add ftrace self-test for empty arguments events

Tests to ensure events that has empty arguments can input trace record
correctly when using ftrace.

Link: https://lkml.kernel.org/r/20230606062027.1008398-3-sunliming@kylinos.cn
Acked-by: Beau Belgrave <beaub@linux.microsoft.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: sunliming <sunliming@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c
index 6e8c4b4..abfb495 100644 (file)
--- a/tools/testing/selftests/user_events/ftrace_test.c
+++ b/tools/testing/selftests/user_events/ftrace_test.c
@@ -316,6 +316,39 @@ TEST_F(user, write_events) {
        ASSERT_EQ(EINVAL, errno);
 }
 
+TEST_F(user, write_empty_events) {
+       struct user_reg reg = {0};
+       struct iovec io[1];
+       int before = 0, after = 0;
+
+       reg.size = sizeof(reg);
+       reg.name_args = (__u64)"__test_event";
+       reg.enable_bit = 31;
+       reg.enable_addr = (__u64)&self->check;
+       reg.enable_size = sizeof(self->check);
+
+       io[0].iov_base = &reg.write_index;
+       io[0].iov_len = sizeof(reg.write_index);
+
+       /* Register should work */
+       ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
+       ASSERT_EQ(0, reg.write_index);
+       ASSERT_EQ(0, self->check);
+
+       /* Enable event */
+       self->enable_fd = open(enable_file, O_RDWR);
+       ASSERT_NE(-1, write(self->enable_fd, "1", sizeof("1")))
+
+       /* Event should now be enabled */
+       ASSERT_EQ(1 << reg.enable_bit, self->check);
+
+       /* Write should make it out to ftrace buffers */
+       before = trace_bytes();
+       ASSERT_NE(-1, writev(self->data_fd, (const struct iovec *)io, 1));
+       after = trace_bytes();
+       ASSERT_GT(after, before);
+}
+
 TEST_F(user, write_fault) {
        struct user_reg reg = {0};
        struct iovec io[2];