From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: Re: [PATCH] mm: kill kmemcheck Date: Wed, 11 Mar 2015 13:25:47 -0400 Message-ID: <55007A9B.4010608@oracle.com> References: <55003666.3020100@oracle.com> <20150311084034.04ce6801@grimm.local.home> <55004595.7020304@oracle.com> <20150311.132052.205877953171712952.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-crypto@vger.kernel.org To: David Miller Return-path: In-Reply-To: <20150311.132052.205877953171712952.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On 03/11/2015 01:20 PM, David Miller wrote: > From: Sasha Levin > Date: Wed, 11 Mar 2015 09:39:33 -0400 > >> > On 03/11/2015 08:40 AM, Steven Rostedt wrote: >>> >> On Wed, 11 Mar 2015 08:34:46 -0400 >>> >> Sasha Levin wrote: >>> >> >>>>> >>> > Fair enough. We knew there are existing kmemcheck users, but KASan should be >>>>> >>> > superior both in performance and the scope of bugs it finds. It also shouldn't >>>>> >>> > impose new limitations beyond requiring gcc 4.9.2+. >>>>> >>> > >>> >> Ouch! OK, then I can't use it. I'm currently compiling with gcc 4.6.3. >>> >> >>> >> It will be a while before I upgrade my build farm to something newer. >> > >> > Are you actually compiling new kernels with 4.6.3, or are you using older >> > kernels as well? >> > >> > There's no real hurry to kill kmemcheck right now, but we do want to stop >> > supporting that in favour of KASan. > Is the spectrum of CPU's supported by this GCC feature equal to all of the > CPU's supported by the kernel right now? > > If not, removing kmemcheck will always be a regression for someone. You're probably wondering why there are changes to SPARC in that patchset? :) I don't really know. Both kmemcheck and KASan run only on x86. I've also asked Vegard, who didn't know either... I guess it got copy-pasted from a different code. As far as I know the only regression is requiring newer GCC. Thanks, Sasha 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 00DEC900049 for ; Wed, 11 Mar 2015 13:26:04 -0400 (EDT) Received: by pablj1 with SMTP id lj1so12957600pab.10 for ; Wed, 11 Mar 2015 10:26:03 -0700 (PDT) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id a4si26967pdn.18.2015.03.11.10.26.00 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 11 Mar 2015 10:26:02 -0700 (PDT) Message-ID: <55007A9B.4010608@oracle.com> Date: Wed, 11 Mar 2015 13:25:47 -0400 From: Sasha Levin MIME-Version: 1.0 Subject: Re: [PATCH] mm: kill kmemcheck References: <55003666.3020100@oracle.com> <20150311084034.04ce6801@grimm.local.home> <55004595.7020304@oracle.com> <20150311.132052.205877953171712952.davem@davemloft.net> In-Reply-To: <20150311.132052.205877953171712952.davem@davemloft.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Miller Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-crypto@vger.kernel.org On 03/11/2015 01:20 PM, David Miller wrote: > From: Sasha Levin > Date: Wed, 11 Mar 2015 09:39:33 -0400 > >> > On 03/11/2015 08:40 AM, Steven Rostedt wrote: >>> >> On Wed, 11 Mar 2015 08:34:46 -0400 >>> >> Sasha Levin wrote: >>> >> >>>>> >>> > Fair enough. We knew there are existing kmemcheck users, but KASan should be >>>>> >>> > superior both in performance and the scope of bugs it finds. It also shouldn't >>>>> >>> > impose new limitations beyond requiring gcc 4.9.2+. >>>>> >>> > >>> >> Ouch! OK, then I can't use it. I'm currently compiling with gcc 4.6.3. >>> >> >>> >> It will be a while before I upgrade my build farm to something newer. >> > >> > Are you actually compiling new kernels with 4.6.3, or are you using older >> > kernels as well? >> > >> > There's no real hurry to kill kmemcheck right now, but we do want to stop >> > supporting that in favour of KASan. > Is the spectrum of CPU's supported by this GCC feature equal to all of the > CPU's supported by the kernel right now? > > If not, removing kmemcheck will always be a regression for someone. You're probably wondering why there are changes to SPARC in that patchset? :) I don't really know. Both kmemcheck and KASan run only on x86. I've also asked Vegard, who didn't know either... I guess it got copy-pasted from a different code. As far as I know the only regression is requiring newer GCC. Thanks, Sasha -- 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