From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754899AbbCLRk7 (ORCPT ); Thu, 12 Mar 2015 13:40:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44743 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754122AbbCLRk4 (ORCPT ); Thu, 12 Mar 2015 13:40:56 -0400 Date: Thu, 12 Mar 2015 18:39:01 +0100 From: Oleg Nesterov To: Andy Lutomirski Cc: Jan Kratochvil , Sergio Durigan Junior , GDB Patches , Pedro Alves , "linux-kernel@vger.kernel.org" Subject: Re: vvar, gup && coredump Message-ID: <20150312173901.GA12225@redhat.com> References: <878ufc9kau.fsf@redhat.com> <20150305154827.GA9441@host1.jankratochvil.net> <87zj7r5fpz.fsf@redhat.com> <20150305205744.GA13165@host1.jankratochvil.net> <20150311200052.GA22654@redhat.com> <20150312143438.GA4338@redhat.com> <20150312165423.GA10073@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/12, Andy Lutomirski wrote: > > On Thu, Mar 12, 2015 at 9:54 AM, Oleg Nesterov wrote: > > On 03/12, Andy Lutomirski wrote: > >> > > As for 32-bit applications. Yes, this can't work because 32-bit simply > > can't access this "high" memory. But you know, it would be very nice to > > have the fixmap-like "global" area in init_mm which is also visible to > > compat applications. If we had it, uprobes could work without xol vma's. > > > It could work for 32-bit native, but not for 32-bit compat. Yes, yes, I meant 32-bit compat apps. Once again, it would be nice if we had the "low" fixmaps in init_mm. But unlikely this is possible... > On a related note, I'm hoping to rework the mm part pretty heavily: > > http://lkml.kernel.org/r/cover.1414629045.git.luto@amacapital.net OK... not that I really understand this email. Well. Speaking of vdso. I understand that unlikely we can do this, but for uprobes it would be nice to have a anon-inode file behind this mapping, so that vma_interval_tree_foreach() could work, etc. OK, this is completely off-topic, please forget. And I noticed that I didn't read your previous email carefully enough... > That sounds reasonable to me. I'll write the patch later today. Sure, please send a patch if you want to do this. > gdb will still need changes, though, right? This is up to gdb developers. To me, it should simply skip this VM_DONTDUMP vma. Oleg.