From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754546AbcEELwq (ORCPT ); Thu, 5 May 2016 07:52:46 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:35436 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751270AbcEELwp (ORCPT ); Thu, 5 May 2016 07:52:45 -0400 Date: Thu, 5 May 2016 13:52:40 +0200 From: Ingo Molnar To: Dmitry Safonov Cc: Andy Lutomirski , Ingo Molnar , "linux-kernel@vger.kernel.org" , Thomas Gleixner , "H. Peter Anvin" , X86 ML , Andrew Morton , "linux-mm@kvack.org" , Dmitry Safonov <0x7f454c46@gmail.com> Subject: Re: [PATCHv8 1/2] x86/vdso: add mremap hook to vm_special_mapping Message-ID: <20160505115240.GA29616@gmail.com> References: <1460388169-13340-1-git-send-email-dsafonov@virtuozzo.com> <1461584223-9418-1-git-send-email-dsafonov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Dmitry Safonov wrote: > On 04/26/2016 12:38 AM, Andy Lutomirski wrote: > >On Mon, Apr 25, 2016 at 4:37 AM, Dmitry Safonov wrote: > >>Add possibility for userspace 32-bit applications to move > >>vdso mapping. Previously, when userspace app called > >>mremap for vdso, in return path it would land on previous > >>address of vdso page, resulting in segmentation violation. > >>Now it lands fine and returns to userspace with remapped vdso. > >>This will also fix context.vdso pointer for 64-bit, which does not > >>affect the user of vdso after mremap by now, but this may change. > >> > >>As suggested by Andy, return EINVAL for mremap that splits vdso image. > >> > >>Renamed and moved text_mapping structure declaration inside > >>map_vdso, as it used only there and now it complement > >>vvar_mapping variable. > >> > >>There is still problem for remapping vdso in glibc applications: > >>linker relocates addresses for syscalls on vdso page, so > >>you need to relink with the new addresses. Or the next syscall > >>through glibc may fail: > >> Program received signal SIGSEGV, Segmentation fault. > >> #0 0xf7fd9b80 in __kernel_vsyscall () > >> #1 0xf7ec8238 in _exit () from /usr/lib32/libc.so.6 > >Acked-by: Andy Lutomirski > > > >Ingo, can you apply this? > > Hm, so I'm not sure - should I resend those two? > Or just ping? Please send a clean series with updated Acked-by's, etc. Thanks! Ingo