From patchwork Fri Sep 8 20:01:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 13377788 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 65E77EEB566 for ; Fri, 8 Sep 2023 20:01:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233916AbjIHUBp (ORCPT ); Fri, 8 Sep 2023 16:01:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230457AbjIHUBo (ORCPT ); Fri, 8 Sep 2023 16:01:44 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 196498E; Fri, 8 Sep 2023 13:01:41 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20079C433C8; Fri, 8 Sep 2023 20:01:40 +0000 (UTC) Date: Fri, 8 Sep 2023 16:01:57 -0400 From: Steven Rostedt To: LKML , Linux Trace Devel Cc: Masami Hiramatsu , Mark Rutland , Sven Schnelle Subject: [PATCH] tracing/synthetic: Fix order of struct trace_dynamic_info Message-ID: <20230908160157.1152301f@gandalf.local.home> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: "Steven Rostedt (Google)" To make handling BIG and LITTLE endian better the offset/len of dynamic fields of the synthetic events was changed into a structure of: struct trace_dynamic_info { #ifdef CONFIG_CPU_BIG_ENDIAN u16 offset; u16 len; #else u16 len; u16 offset; #endif }; to replace the manual changes of: data_offset = offset & 0xffff; data_offest = len << 16; But if you look closely, the above is: << 16 | offset Which in little endian would be in memory: offset_lo offset_hi len_lo len_hi and in big endian: len_hi len_lo offset_hi offset_lo Which if broken into a structure would be: struct trace_dynamic_info { #ifdef CONFIG_CPU_BIG_ENDIAN u16 len; u16 offset; #else u16 offset; u16 len; #endif }; Which is the opposite of what was defined. Fix this and just to be safe also add "__packed". Link: https://lore.kernel.org/all/20230908154417.5172e343@gandalf.local.home/ Cc: stable@vger.kernel.org Fixes: ddeea494a16f3 ("tracing/synthetic: Use union instead of casts") Signed-off-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu (Google) --- include/linux/trace_events.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 12f875e9e69a..21ae37e49319 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -62,13 +62,13 @@ void trace_event_printf(struct trace_iterator *iter, const char *fmt, ...); /* Used to find the offset and length of dynamic fields in trace events */ struct trace_dynamic_info { #ifdef CONFIG_CPU_BIG_ENDIAN - u16 offset; u16 len; + u16 offset; #else - u16 len; u16 offset; + u16 len; #endif -}; +} __packed; /* * The trace entry - the most basic unit of tracing. This is what