From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f51.google.com (mail-pa0-f51.google.com [209.85.220.51]) by kanga.kvack.org (Postfix) with ESMTP id 522956B0031 for ; Sat, 18 Jan 2014 03:41:57 -0500 (EST) Received: by mail-pa0-f51.google.com with SMTP id ld10so2768035pab.38 for ; Sat, 18 Jan 2014 00:41:56 -0800 (PST) Received: from szxga01-in.huawei.com (szxga01-in.huawei.com. [119.145.14.64]) by mx.google.com with ESMTPS id xa2si12656148pab.171.2014.01.18.00.41.53 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sat, 18 Jan 2014 00:41:56 -0800 (PST) Message-ID: <52DA3E41.9050202@huawei.com> Date: Sat, 18 Jan 2014 16:41:37 +0800 From: Jianguo Wu MIME-Version: 1.0 Subject: Re: [PATCH] mm/kmemleak: add support for re-enable kmemleak at runtime References: <52D8FA72.8080100@huawei.com> <20140117120436.GC28895@arm.com> In-Reply-To: <20140117120436.GC28895@arm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Catalin Marinas Cc: Andrew Morton , "rob@landley.net" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Li Zefan , Wang Nan On 2014/1/17 20:04, Catalin Marinas wrote: > On Fri, Jan 17, 2014 at 09:40:02AM +0000, Jianguo Wu wrote: >> Now disabling kmemleak is an irreversible operation, but sometimes >> we may need to re-enable kmemleak at runtime. So add a knob to enable >> kmemleak at runtime: >> echo on > /sys/kernel/debug/kmemleak > > It is irreversible for very good reason: once it missed the initial > memory allocations, there is no way for kmemleak to build the object > reference graph and you'll get lots of false positives, pretty much > making it unusable. > Do you mean we didn't trace memory allocations during kmemleak disable period, and these memory may reference to new allocated objects after re-enable? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org