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 X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6E76C35257 for ; Fri, 2 Oct 2020 22:04:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DBF42072E for ; Fri, 2 Oct 2020 22:04:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601676290; bh=EDDwAOV0ZwyLNQlXhxnuTN6DGHN2lm7tbc8rdKw8T34=; h=Subject:From:To:Cc:Date:In-Reply-To:References:List-ID:From; b=n2wjh2kQClw3RNcPcOODj1jPe2uDj68WkssIjx5imcsqKw6eBRlvXD+RlNEUS9+Zg SAgMFtszO1d9JgwplY8OmeTYlUpxyvP2Ba962MFuoEUq7GXr5mFXL/QFnQSrryelS1 6FcC56VQXekKDkioTySy8f72jb3qAnyFusCzYTVo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725766AbgJBWEt (ORCPT ); Fri, 2 Oct 2020 18:04:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:34332 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725283AbgJBWEt (ORCPT ); Fri, 2 Oct 2020 18:04:49 -0400 Received: from tzanussi-mobl (c-73-209-127-30.hsd1.il.comcast.net [73.209.127.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3C11320719; Fri, 2 Oct 2020 22:04:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601676288; bh=EDDwAOV0ZwyLNQlXhxnuTN6DGHN2lm7tbc8rdKw8T34=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=1lN6jaNHJds8vh4DCPahKoVdOq3+GNhZJXt0rtwWahwlFu1KrLOHAZzN56NMQQpXg s2QjsspYb37CWL4Y59B4kyEWePh4Iw6NGeSjOhtHrXOE7bIkmcXmxZ4tqpSbR2B+pb FWMBq5HvcWfUXK8b77INoTtGVDMf6bBklnAShm+w= Message-ID: <75577192da2769b982b748305ad5609d94bd9bcf.camel@kernel.org> Subject: Re: [PATCH v3 1/3] tracing: Change STR_VAR_MAX_LEN From: Tom Zanussi To: Steven Rostedt Cc: axelrasmussen@google.com, mhiramat@kernel.org, linux-kernel@vger.kernel.org Date: Fri, 02 Oct 2020 17:04:46 -0500 In-Reply-To: <20201002154417.320ad78b@gandalf.local.home> References: <34a494e502fe1364b07896ef4d76f1fbbb8d1d1a.1601588066.git.zanussi@kernel.org> <20201002154417.320ad78b@gandalf.local.home> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steve, On Fri, 2020-10-02 at 15:44 -0400, Steven Rostedt wrote: > On Thu, 1 Oct 2020 16:46:44 -0500 > Tom Zanussi wrote: > > > 32 is too small for this value, and anyway it makes more sense to > > use > > MAX_FILTER_STR_VAL, as this is also the value used for variable- > > length > > __strings. > > > > Tested-by: Axel Rasmussen > > Signed-off-by: Tom Zanussi > > --- > > kernel/trace/trace_synth.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/trace/trace_synth.h > > b/kernel/trace/trace_synth.h > > index ac35c45207c4..5166705d1556 100644 > > --- a/kernel/trace/trace_synth.h > > +++ b/kernel/trace/trace_synth.h > > @@ -7,7 +7,7 @@ > > #define SYNTH_SYSTEM "synthetic" > > #define SYNTH_FIELDS_MAX 32 > > > > -#define STR_VAR_LEN_MAX 32 /* must be multiple of > > sizeof(u64) */ > > +#define STR_VAR_LEN_MAX MAX_FILTER_STR_VAL /* must be > > multiple of sizeof(u64) */ > > Hmm, this requirement is now passed to MAX_FILTER_STR_VAL, but > there's no > mention of it there. I guess we should have a > > BUILD_BUG_ON(STR_VAR_LEN_MAX & (sizeof(u64) - 1)); > > in C code somewhere. Good point. I'll add that in the next version. Thanks, Tom