From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754703AbaFNMF0 (ORCPT ); Sat, 14 Jun 2014 08:05:26 -0400 Received: from mail-wg0-f48.google.com ([74.125.82.48]:35879 "EHLO mail-wg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753767AbaFNMFZ convert rfc822-to-8bit (ORCPT ); Sat, 14 Jun 2014 08:05:25 -0400 Subject: Re: kmemleak: Unable to handle kernel paging request Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.2\)) Content-Type: text/plain; charset=windows-1252 From: Catalin Marinas In-Reply-To: <1402695853.20360.17.camel@pasglop> Date: Sat, 14 Jun 2014 13:05:18 +0100 Cc: Denis Kirjanov , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Naoya Horiguchi , "linuxppc-dev@lists.ozlabs.org" , Paul Mackerras Content-Transfer-Encoding: 8BIT Message-Id: References: <20140611173851.GA5556@MacBook-Pro.local> <20140612143916.GB8970@arm.com> <20140613085640.GA21018@arm.com> <1402695853.20360.17.camel@pasglop> To: Benjamin Herrenschmidt X-Mailer: Apple Mail (2.1878.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13 Jun 2014, at 22:44, Benjamin Herrenschmidt wrote: > On Fri, 2014-06-13 at 09:56 +0100, Catalin Marinas wrote: > >> OK, so that's the DART table allocated via alloc_dart_table(). Is >> dart_tablebase removed from the kernel linear mapping after allocation? > > Yes. > >> If that's the case, we need to tell kmemleak to ignore this block (see >> patch below, untested). But I still can't explain how commit >> d4c54919ed863020 causes this issue. >> >> (also cc'ing the powerpc list and maintainers) > > We remove the DART from the linear mapping because it has to be mapped > non-cachable and having it in the linear mapping would cause cache > paradoxes. We also can't just change the caching attributes in the > linear mapping because we use 16M pages for it and 970 CPUs don't > support cache-inhibited 16M pages :-( And due to the MMU segmentation > model, we also can't mix & match page sizes in that area. > > So we just unmap it, and ioremap it elsewhere. OK, thanks for the explanation. So the kmemleak annotation makes sense. Would you please take the I patch earlier (I guess with Denis’ tested- by). I can send it separately if more convenient. Thanks, Catalin