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