From nobody Sun Feb 8 15:08:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99B40EB64DD for ; Fri, 23 Jun 2023 19:29:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231559AbjFWT3d (ORCPT ); Fri, 23 Jun 2023 15:29:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229446AbjFWT3b (ORCPT ); Fri, 23 Jun 2023 15:29:31 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BECAD2705 for ; Fri, 23 Jun 2023 12:29:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 501FE61B04 for ; Fri, 23 Jun 2023 19:29:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6455C433CA; Fri, 23 Jun 2023 19:29:27 +0000 (UTC) Date: Fri, 23 Jun 2023 15:29:26 -0400 From: Steven Rostedt To: Linus Torvalds Cc: LKML , Masami Hiramatsu , Mark Rutland , Beau Belgrave , Andrew Morton , sunliming Subject: [GIT PULL] tracing: user_event fix for 6.4 Message-ID: <20230623152926.128aa568@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Linus, Tracing fix to user events return value on write Before user events become an ABI, fix the return value of the write operation when tracing is disabled. It should not return an error, but simply report it wrote zero bytes. Just like any other write operation that doesn't write data but does not "fail". This also includes test cases for this use case. Please pull the latest trace-v6.4-rc7 tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git trace-v6.4-rc7 Tag SHA1: ec925ce3a8456d2a527572e940ed52123a6083cd Head SHA1: 131966049074b8025a8cba0e99d3745311fcef5b sunliming (3): tracing/user_events: Fix incorrect return value for writing operation= when events are disabled selftests/user_events: Enable the event before write_fault test in ft= race self-test selftests/user_events: Add test cases when event is disabled ---- kernel/trace/trace_events_user.c | 3 ++- tools/testing/selftests/user_events/ftrace_test.c | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletion(-) --------------------------- diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_u= ser.c index 8df0550415e7..902cae005df4 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -2096,7 +2096,8 @@ static ssize_t user_events_write_core(struct file *fi= le, struct iov_iter *i) =20 if (unlikely(faulted)) return -EFAULT; - } + } else + return 0; =20 return ret; } diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/test= ing/selftests/user_events/ftrace_test.c index eb6904d89f14..f42a20520175 100644 --- a/tools/testing/selftests/user_events/ftrace_test.c +++ b/tools/testing/selftests/user_events/ftrace_test.c @@ -324,6 +324,9 @@ TEST_F(user, write_events) { io[0].iov_base =3D ®.write_index; io[0].iov_len =3D sizeof(reg.write_index); =20 + /* Write should return zero when event is not enabled */ + ASSERT_EQ(0, writev(self->data_fd, (const struct iovec *)io, 3)); + /* Enable event */ self->enable_fd =3D open(enable_file, O_RDWR); ASSERT_NE(-1, write(self->enable_fd, "1", sizeof("1"))) @@ -400,6 +403,10 @@ TEST_F(user, write_fault) { ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, ®)); ASSERT_EQ(0, reg.write_index); =20 + /* Enable event */ + self->enable_fd =3D open(enable_file, O_RDWR); + ASSERT_NE(-1, write(self->enable_fd, "1", sizeof("1"))) + /* Write should work normally */ ASSERT_NE(-1, writev(self->data_fd, (const struct iovec *)io, 2));