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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 A7B28C433F4 for ; Fri, 31 Aug 2018 14:56:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5AE912077C for ; Fri, 31 Aug 2018 14:56:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5AE912077C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728833AbeHaTEJ (ORCPT ); Fri, 31 Aug 2018 15:04:09 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:59944 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728590AbeHaTEJ (ORCPT ); Fri, 31 Aug 2018 15:04:09 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5DC6B7A9; Fri, 31 Aug 2018 07:56:17 -0700 (PDT) Received: from armageddon.cambridge.arm.com (armageddon.emea.arm.com [10.4.13.16]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 722753F5BD; Fri, 31 Aug 2018 07:56:16 -0700 (PDT) Date: Fri, 31 Aug 2018 15:56:13 +0100 From: Catalin Marinas To: Vincent Whitchurch Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv2] kmemleak: Add option to print warnings to dmesg Message-ID: <20180831145613.6cxtk3j5m4amxtoh@armageddon.cambridge.arm.com> References: <20180827083821.7706-1-vincent.whitchurch@axis.com> <20180827151641.59bdca4e1ea2e532b10cd9fd@linux-foundation.org> <20180828101412.mb7t562roqbhsbjw@axis.com> <20180828102621.yawpcrkikhh4kagv@armageddon.cambridge.arm.com> <20180830074327.ivjq6g25lw7kpz2l@axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180830074327.ivjq6g25lw7kpz2l@axis.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 30, 2018 at 09:43:27AM +0200, Vincent Whitchurch wrote: > On Tue, Aug 28, 2018 at 11:26:22AM +0100, Catalin Marinas wrote: > > On Tue, Aug 28, 2018 at 12:14:12PM +0200, Vincent Whitchurch wrote: > > > On Mon, Aug 27, 2018 at 03:16:41PM -0700, Andrew Morton wrote: > > > > On Mon, 27 Aug 2018 10:38:21 +0200 Vincent Whitchurch wrote: > > > > > +config DEBUG_KMEMLEAK_WARN > > > > > + bool "Print kmemleak object warnings to log buffer" > > > > > + depends on DEBUG_KMEMLEAK > > > > > + help > > > > > + Say Y here to make kmemleak print information about unreferenced > > > > > + objects (including stacktraces) as warnings to the kernel log buffer. > > > > > + Otherwise this information is only available by reading the kmemleak > > > > > + debugfs file. > > > > > > > > Why add the config option? Why not simply make the change for all > > > > configs? > > > > > > No particular reason other than preserving the current behaviour for > > > existing users. I can remove the config option if Catalin is fine with > > > it. > > > > IIRC, in the early kmemleak days, people complained about it being to > > noisy (the false positives rate was also much higher), so the default > > behaviour was changed to monitor (almost) quietly with the details > > available via debugfs. I'd like to keep this default behaviour but we > > could have a "verbose" command via both debugfs and kernel parameter (as > > we do with "off" and "on"). Would this work for you? > > Either a config option or a parameter are usable for me. How about > something like this? It can be enabled with kmemleak.verbose=1 or "echo > 1 > /sys/module/kmemleak/parameters/verbose": Works for me (slightly inconsistent with "echo ... > /sys/kernel/debug/kmemleak" but a module_param seems to work better here as it's a configuration rather than an action). -- Catalin