From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f198.google.com (mail-ob0-f198.google.com [209.85.214.198]) by kanga.kvack.org (Postfix) with ESMTP id 347256B0005 for ; Thu, 5 May 2016 07:56:34 -0400 (EDT) Received: by mail-ob0-f198.google.com with SMTP id rd14so166240260obb.3 for ; Thu, 05 May 2016 04:56:34 -0700 (PDT) Received: from emea01-am1-obe.outbound.protection.outlook.com (mail-am1on0146.outbound.protection.outlook.com. [157.56.112.146]) by mx.google.com with ESMTPS id 197si3658075oia.13.2016.05.05.04.56.33 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 05 May 2016 04:56:33 -0700 (PDT) Subject: Re: [PATCHv8 1/2] x86/vdso: add mremap hook to vm_special_mapping References: <1460388169-13340-1-git-send-email-dsafonov@virtuozzo.com> <1461584223-9418-1-git-send-email-dsafonov@virtuozzo.com> <20160505115240.GA29616@gmail.com> From: Dmitry Safonov Message-ID: <70acdc9f-8980-0488-2d52-49a90c4b6a59@virtuozzo.com> Date: Thu, 5 May 2016 14:55:12 +0300 MIME-Version: 1.0 In-Reply-To: <20160505115240.GA29616@gmail.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar 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> On 05/05/2016 02:52 PM, Ingo Molnar wrote: > > * 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, will do. Sorry for html in the last email - mail agent got an update and I overlooked html composing become turned on. -- Regards, Dmitry Safonov -- 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