From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ve0-f181.google.com (mail-ve0-f181.google.com [209.85.128.181]) by kanga.kvack.org (Postfix) with ESMTP id 72D166B0036 for ; Wed, 14 May 2014 18:52:20 -0400 (EDT) Received: by mail-ve0-f181.google.com with SMTP id pa12so299631veb.40 for ; Wed, 14 May 2014 15:52:20 -0700 (PDT) Received: from mail-ve0-f175.google.com (mail-ve0-f175.google.com [209.85.128.175]) by mx.google.com with ESMTPS id gu9si570300vdc.160.2014.05.14.15.52.19 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 14 May 2014 15:52:19 -0700 (PDT) Received: by mail-ve0-f175.google.com with SMTP id jw12so310863veb.6 for ; Wed, 14 May 2014 15:52:19 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20140514143124.52c598a2ba8e2539ee76558c@linux-foundation.org> References: <53739201.6080604@oracle.com> <20140514132312.573e5d3cf99276c3f0b82980@linux-foundation.org> <5373D509.7090207@oracle.com> <20140514140305.7683c1c2f1e4fb0a63085a2a@linux-foundation.org> <5373DBE4.6030907@oracle.com> <20140514143124.52c598a2ba8e2539ee76558c@linux-foundation.org> From: Andy Lutomirski Date: Wed, 14 May 2014 15:51:59 -0700 Message-ID: Subject: Re: mm: NULL ptr deref handling mmaping of special mappings Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Sasha Levin , "linux-mm@kvack.org" , Dave Jones , LKML On Wed, May 14, 2014 at 2:31 PM, Andrew Morton wrote: > On Wed, 14 May 2014 17:11:00 -0400 Sasha Levin wrote: > >> > In my linux-next all that code got deleted by Andy's "x86, vdso: >> > Reimplement vdso.so preparation in build-time C" anyway. What kernel >> > were you looking at? >> >> Deleted? It appears in today's -next. arch/x86/vdso/vma.c:124 . >> >> I don't see Andy's patch removing that code either. > > ah, OK, it got moved from arch/x86/vdso/vdso32-setup.c into > arch/x86/vdso/vma.c. > > Maybe you managed to take a fault against the symbol area between the > _install_special_mapping() and the remap_pfn_range() call, but mmap_sem > should prevent that. > > Or the remap_pfn_range() call never happened. Should map_vdso() be > running _install_special_mapping() at all if > image->sym_vvar_page==NULL? You're almost right, but that was enough to point me in the right direction :) The mapping is still needed, since there are two pages. qemu -no-hpet will trigger this, but the nohpet kernel option will not. The latter is arguably a bug in the nohpet option. Fix coming. -- Andy Lutomirski AMA Capital Management, LLC -- 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