From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 424E9C6778F for ; Tue, 24 Jul 2018 20:03:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E833F20880 for ; Tue, 24 Jul 2018 20:03:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E833F20880 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388713AbeGXVLO (ORCPT ); Tue, 24 Jul 2018 17:11:14 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51236 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388450AbeGXVLO (ORCPT ); Tue, 24 Jul 2018 17:11:14 -0400 Received: from akpm3.svl.corp.google.com (unknown [104.133.9.92]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 7EE63D27; Tue, 24 Jul 2018 20:03:09 +0000 (UTC) Date: Tue, 24 Jul 2018 13:03:08 -0700 From: Andrew Morton To: "Kirill A. Shutemov" Cc: Linus Torvalds , Dmitry Vyukov , Oleg Nesterov , Andrea Arcangeli , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCHv3 1/3] mm: Introduce vma_init() Message-Id: <20180724130308.bbd46afc3703af4c5e1d6868@linux-foundation.org> In-Reply-To: <20180724121139.62570-2-kirill.shutemov@linux.intel.com> References: <20180724121139.62570-1-kirill.shutemov@linux.intel.com> <20180724121139.62570-2-kirill.shutemov@linux.intel.com> X-Mailer: Sylpheed 3.6.0 (GTK+ 2.24.31; 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 24 Jul 2018 15:11:37 +0300 "Kirill A. Shutemov" wrote: > Not all VMAs allocated with vm_area_alloc(). Some of them allocated on > stack or in data segment. > > The new helper can be use to initialize VMA properly regardless where > it was allocated. > > ... > > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -452,6 +452,12 @@ struct vm_operations_struct { > unsigned long addr); > }; > > +static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) > +{ > + vma->vm_mm = mm; > + INIT_LIST_HEAD(&vma->anon_vma_chain); > +} > + > struct mmu_gather; > struct inode; > > diff --git a/kernel/fork.c b/kernel/fork.c > index a191c05e757d..1b27babc4c78 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -312,10 +312,8 @@ struct vm_area_struct *vm_area_alloc(struct mm_struct *mm) > { > struct vm_area_struct *vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); I'd sleep better if this became a kmem_cache_alloc() and the memset was moved into vma_init(). A bunch of the vma_init() callers are already doing the memset and the others risk leaving uninitialized stack fields in the vma. > > - if (vma) { > - vma->vm_mm = mm; > - INIT_LIST_HEAD(&vma->anon_vma_chain); > - } > + if (vma) > + vma_init(vma, mm); > return vma; > }