From mboxrd@z Thu Jan 1 00:00:00 1970 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 6D16CC77B73 for ; Mon, 8 May 2023 10:18:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234358AbjEHKSy (ORCPT ); Mon, 8 May 2023 06:18:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234352AbjEHKSx (ORCPT ); Mon, 8 May 2023 06:18:53 -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 B67D8D2DF for ; Mon, 8 May 2023 03:18:51 -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 4E8E162509 for ; Mon, 8 May 2023 10:18:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67EC5C4339C; Mon, 8 May 2023 10:18:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1683541130; bh=FGAll/LomuNzjHZoRmGPenTV7BFTpGFr4ZGudxmlivI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dJPPgX4b75/xCIhm8q13uF35IOshFNPeax838QEZd8bgwYshiJ7wcdyHPIGhIdkwz X6RxpZwuQ1MnVtO/Nvw2gzbEDV/RQrnJQYfpiQcjy4ZWHhKXJMWxcrLoaYA220/1IP xfrGupchr5wvIGf4h+T32/BIRLgztpwg32f2gWuo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Douglas RAILLARD , "Steven Rostedt (Google)" , "Masami Hiramatsu (Google)" , Sasha Levin Subject: [PATCH 6.2 016/663] tracing: Error if a trace event has an array for a __field() Date: Mon, 8 May 2023 11:37:22 +0200 Message-Id: <20230508094428.953862813@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230508094428.384831245@linuxfoundation.org> References: <20230508094428.384831245@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Steven Rostedt (Google) [ Upstream commit f82e7ca019dfad3b006fd3b772f7ac569672db55 ] A __field() in the TRACE_EVENT() macro is used to set up the fields of the trace event data. It is for single storage units (word, char, int, pointer, etc) and not for complex structures or arrays. Unfortunately, there's nothing preventing the build from accepting: __field(int, arr[5]); from building. It will turn into a array value. This use to work fine, as the offset and size use to be determined by the macro using the field name, but things have changed and the offset and size are now determined by the type. So the above would only be size 4, and the next field will be located 4 bytes from it (instead of 20). The proper way to declare static arrays is to use the __array() macro. Instead of __field(int, arr[5]) it should be __array(int, arr, 5). Add some macro tricks to the building of a trace event from the TRACE_EVENT() macro such that __field(int, arr[5]) will fail to build. A comment by the failure will explain why the build failed. Link: https://lore.kernel.org/lkml/20230306122549.236561-1-douglas.raillard@arm.com/ Link: https://lore.kernel.org/linux-trace-kernel/20230309221302.642e82d9@gandalf.local.home Reported-by: Douglas RAILLARD Signed-off-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu (Google) Signed-off-by: Sasha Levin --- include/trace/stages/stage5_get_offsets.h | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/include/trace/stages/stage5_get_offsets.h b/include/trace/stages/stage5_get_offsets.h index ac5c24d3beeb2..e30a13be46ba5 100644 --- a/include/trace/stages/stage5_get_offsets.h +++ b/include/trace/stages/stage5_get_offsets.h @@ -9,17 +9,30 @@ #undef __entry #define __entry entry +/* + * Fields should never declare an array: i.e. __field(int, arr[5]) + * If they do, it will cause issues in parsing and possibly corrupt the + * events. To prevent that from happening, test the sizeof() a fictitious + * type called "struct _test_no_array_##item" which will fail if "item" + * contains array elements (like "arr[5]"). + * + * If you hit this, use __array(int, arr, 5) instead. + */ #undef __field -#define __field(type, item) +#define __field(type, item) \ + { (void)sizeof(struct _test_no_array_##item *); } #undef __field_ext -#define __field_ext(type, item, filter_type) +#define __field_ext(type, item, filter_type) \ + { (void)sizeof(struct _test_no_array_##item *); } #undef __field_struct -#define __field_struct(type, item) +#define __field_struct(type, item) \ + { (void)sizeof(struct _test_no_array_##item *); } #undef __field_struct_ext -#define __field_struct_ext(type, item, filter_type) +#define __field_struct_ext(type, item, filter_type) \ + { (void)sizeof(struct _test_no_array_##item *); } #undef __array #define __array(type, item, len) -- 2.39.2