From patchwork Sun Jul 3 13:14:49 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12904338 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 B1342C43334 for ; Sun, 3 Jul 2022 13:14:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232636AbiGCNOz (ORCPT ); Sun, 3 Jul 2022 09:14:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232640AbiGCNOy (ORCPT ); Sun, 3 Jul 2022 09:14:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5475463F2; Sun, 3 Jul 2022 06:14:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E5E0360AC0; Sun, 3 Jul 2022 13:14:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFAF6C341C6; Sun, 3 Jul 2022 13:14:50 +0000 (UTC) Date: Sun, 3 Jul 2022 09:14:49 -0400 From: Steven Rostedt To: LKML Cc: Felipe Balbi , Greg Kroah-Hartman , linux-usb@vger.kernel.org Subject: [PATCH v2] USB: gadget: udc: tracing: Do not open code __string() with __dynamic_array() Message-ID: <20220703091449.317f94b1@rorschach.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: "Steven Rostedt (Google)" The event classes udc_log_ep and udc_log_req both declare: __dynamic_array(char, name, UDC_TRACE_STR_MAX) Which will reserve UDC_TRACE_STR_MAX bytes on the ring buffer for the event to write in name. It then uses snprintf() to write into that space. Assuming that the string being copied is nul terminated, it is better to just use the __string() helper. That way only the size of the string is saved into the ring buffer and not the max size (yes, the entire UDC_TRACE_STR_MAX is used in the trace event, and anything not used is just junk in the ring buffer). Worse, there's also meta data saved into the event that denotes where the string is stored in the event and also saves its size, which is always going to be UDC_TRACE_STR_MAX. Convert both to use the __string() and __assign_str() helpers that are for this kind of use case. Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org Signed-off-by: Steven Rostedt (Google) --- Changes since v1: Link: https://lkml.kernel.org/r/20220702200127.399d2358@gandalf.local.home - Commit the fix to the extra semicolon that I found compiling the code, but forgot to do a commit --amend before sending. drivers/usb/gadget/udc/trace.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/usb/gadget/udc/trace.h b/drivers/usb/gadget/udc/trace.h index 98584f6b6c66..abdbcb1bacb0 100644 --- a/drivers/usb/gadget/udc/trace.h +++ b/drivers/usb/gadget/udc/trace.h @@ -140,7 +140,7 @@ DECLARE_EVENT_CLASS(udc_log_ep, TP_PROTO(struct usb_ep *ep, int ret), TP_ARGS(ep, ret), TP_STRUCT__entry( - __dynamic_array(char, name, UDC_TRACE_STR_MAX) + __string(name, ep->name) __field(unsigned, maxpacket) __field(unsigned, maxpacket_limit) __field(unsigned, max_streams) @@ -152,7 +152,7 @@ DECLARE_EVENT_CLASS(udc_log_ep, __field(int, ret) ), TP_fast_assign( - snprintf(__get_str(name), UDC_TRACE_STR_MAX, "%s", ep->name); + __assign_str(name, ep->name); __entry->maxpacket = ep->maxpacket; __entry->maxpacket_limit = ep->maxpacket_limit; __entry->max_streams = ep->max_streams; @@ -214,7 +214,7 @@ DECLARE_EVENT_CLASS(udc_log_req, TP_PROTO(struct usb_ep *ep, struct usb_request *req, int ret), TP_ARGS(ep, req, ret), TP_STRUCT__entry( - __dynamic_array(char, name, UDC_TRACE_STR_MAX) + __string(name, ep->name) __field(unsigned, length) __field(unsigned, actual) __field(unsigned, num_sgs) @@ -228,7 +228,7 @@ DECLARE_EVENT_CLASS(udc_log_req, __field(struct usb_request *, req) ), TP_fast_assign( - snprintf(__get_str(name), UDC_TRACE_STR_MAX, "%s", ep->name); + __assign_str(name, ep->name); __entry->length = req->length; __entry->actual = req->actual; __entry->num_sgs = req->num_sgs;