From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f176.google.com (mail-ie0-f176.google.com [209.85.223.176]) by kanga.kvack.org (Postfix) with ESMTP id 476DB6B025D for ; Thu, 23 Jul 2015 16:59:13 -0400 (EDT) Received: by iecri3 with SMTP id ri3so3805546iec.2 for ; Thu, 23 Jul 2015 13:59:13 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id i99si6012164iod.100.2015.07.23.13.59.12 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Jul 2015 13:59:12 -0700 (PDT) Date: Thu, 23 Jul 2015 13:59:11 -0700 From: Andrew Morton Subject: Re: [PATCHv2 2/6] x86, mpx: do not set ->vm_ops on mpx VMAs Message-Id: <20150723135911.af81b6a685f5b779ca66f3c3@linux-foundation.org> In-Reply-To: <1437133993-91885-3-git-send-email-kirill.shutemov@linux.intel.com> References: <1437133993-91885-1-git-send-email-kirill.shutemov@linux.intel.com> <1437133993-91885-3-git-send-email-kirill.shutemov@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Oleg Nesterov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Thomas Gleixner On Fri, 17 Jul 2015 14:53:09 +0300 "Kirill A. Shutemov" wrote: > MPX setups private anonymous mapping, but uses vma->vm_ops too. > This can confuse core VM, as it relies on vm->vm_ops to distinguish > file VMAs from anonymous. > > As result we will get SIGBUS, because handle_pte_fault() thinks it's > file VMA without vm_ops->fault and it doesn't know how to handle the > situation properly. > > Let's fix that by not setting ->vm_ops. > > We don't really need ->vm_ops here: MPX VMA can be detected with VM_MPX > flag. And vma_merge() will not merge MPX VMA with non-MPX VMA, because > ->vm_flags won't match. > > The only thing left is name of VMA. I'm not sure if it's part of ABI, or > we can just drop it. The patch keep it by providing arch_vma_name() on x86. > > Build tested only. mpx.c has changed. arch/x86/mm/mpx.c: In function 'try_unmap_single_bt': arch/x86/mm/mpx.c:930: error: implicit declaration of function 'is_mpx_vma' I'll drop this patch and see what happens. -- 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