From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752958AbaENVb1 (ORCPT ); Wed, 14 May 2014 17:31:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48332 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751418AbaENVb0 (ORCPT ); Wed, 14 May 2014 17:31:26 -0400 Date: Wed, 14 May 2014 14:31:24 -0700 From: Andrew Morton To: Sasha Levin Cc: "linux-mm@kvack.org" , Dave Jones , LKML , Andy Lutomirski Subject: Re: mm: NULL ptr deref handling mmaping of special mappings Message-Id: <20140514143124.52c598a2ba8e2539ee76558c@linux-foundation.org> In-Reply-To: <5373DBE4.6030907@oracle.com> References: <53739201.6080604@oracle.com> <20140514132312.573e5d3cf99276c3f0b82980@linux-foundation.org> <5373D509.7090207@oracle.com> <20140514140305.7683c1c2f1e4fb0a63085a2a@linux-foundation.org> <5373DBE4.6030907@oracle.com> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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?