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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 8D8A9C43461 for ; Fri, 30 Apr 2021 05:57:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FC6061481 for ; Fri, 30 Apr 2021 05:57:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230296AbhD3F6h (ORCPT ); Fri, 30 Apr 2021 01:58:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:51790 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230119AbhD3F6h (ORCPT ); Fri, 30 Apr 2021 01:58:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0414C613A9; Fri, 30 Apr 2021 05:57:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619762269; bh=bxOVP6OviiFNiTxFBJf6DDliT8/5JiIL3hyipcDh3cs=; h=Date:From:To:Subject:In-Reply-To:From; b=tAbDb7KwAbEjzhJqGN/oCq/sEDZj/1hQrdarkxB4oniolMVWSZ6fcbbCtTkeT7s0u Zg0aSaYOjLStj1kAlx70nyend8HfScSQd674p12fZtkQy3GmUh46bcDQs2t3licF2g 8QkRF8GgaVefzkumQXRvQQZmyzVD7dQRsjM36Bek= Date: Thu, 29 Apr 2021 22:57:48 -0700 From: Andrew Morton To: 0x7f454c46@gmail.com, aarcange@redhat.com, akpm@linux-foundation.org, alx.manpages@gmail.com, axelrasmussen@google.com, bgeffon@google.com, hughd@google.com, kirill@shutemov.name, linux-mm@kvack.org, lokeshgidra@google.com, luto@amacapital.net, minchan@kernel.org, mm-commits@vger.kernel.org, mst@redhat.com, mtk.manpages@gmail.com, peterx@redhat.com, rppt@linux.vnet.ibm.com, sonnyrao@google.com, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 090/178] Revert "mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio" Message-ID: <20210430055748.9Cf23vOu6%akpm@linux-foundation.org> In-Reply-To: <20210429225251.02b6386d21b69255b4f6c163@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Brian Geffon Subject: Revert "mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio" This reverts commit cd544fd1dc9293c6702fab6effa63dac1cc67e99. As discussed in [1] this commit was a no-op because the mapping type was checked in vma_to_resize before move_vma is ever called. This meant that vm_ops->mremap() would never be called on such mappings. Furthermore, we've since expanded support of MREMAP_DONTUNMAP to non-anonymous mappings, and these special mappings are still protected by the existing check of !VM_DONTEXPAND and !VM_PFNMAP which will result in a -EINVAL. 1. https://lkml.org/lkml/2020/12/28/2340 Link: https://lkml.kernel.org/r/20210323182520.2712101-2-bgeffon@google.com Signed-off-by: Brian Geffon Acked-by: Hugh Dickins Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Alejandro Colomar Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Axel Rasmussen Cc: "Kirill A . Shutemov" Cc: Lokesh Gidra Cc: Michael Kerrisk Cc: "Michael S . Tsirkin" Cc: Mike Rapoport Cc: Minchan Kim Cc: Peter Xu Cc: Sonny Rao Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 2 +- fs/aio.c | 5 +---- include/linux/mm.h | 2 +- mm/mmap.c | 6 +----- mm/mremap.c | 2 +- 5 files changed, 5 insertions(+), 12 deletions(-) --- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c~revert-mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c @@ -1458,7 +1458,7 @@ static int pseudo_lock_dev_release(struc return 0; } -static int pseudo_lock_dev_mremap(struct vm_area_struct *area, unsigned long flags) +static int pseudo_lock_dev_mremap(struct vm_area_struct *area) { /* Not supported */ return -EINVAL; --- a/fs/aio.c~revert-mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/fs/aio.c @@ -323,16 +323,13 @@ static void aio_free_ring(struct kioctx } } -static int aio_ring_mremap(struct vm_area_struct *vma, unsigned long flags) +static int aio_ring_mremap(struct vm_area_struct *vma) { struct file *file = vma->vm_file; struct mm_struct *mm = vma->vm_mm; struct kioctx_table *table; int i, res = -EINVAL; - if (flags & MREMAP_DONTUNMAP) - return -EINVAL; - spin_lock(&mm->ioctx_lock); rcu_read_lock(); table = rcu_dereference(mm->ioctx_table); --- a/include/linux/mm.h~revert-mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/include/linux/mm.h @@ -580,7 +580,7 @@ struct vm_operations_struct { void (*close)(struct vm_area_struct * area); /* Called any time before splitting to check if it's allowed */ int (*may_split)(struct vm_area_struct *area, unsigned long addr); - int (*mremap)(struct vm_area_struct *area, unsigned long flags); + int (*mremap)(struct vm_area_struct *area); /* * Called by mprotect() to make driver-specific permission * checks before mprotect() is finalised. The VMA must not --- a/mm/mmap.c~revert-mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/mm/mmap.c @@ -3409,14 +3409,10 @@ static const char *special_mapping_name( return ((struct vm_special_mapping *)vma->vm_private_data)->name; } -static int special_mapping_mremap(struct vm_area_struct *new_vma, - unsigned long flags) +static int special_mapping_mremap(struct vm_area_struct *new_vma) { struct vm_special_mapping *sm = new_vma->vm_private_data; - if (flags & MREMAP_DONTUNMAP) - return -EINVAL; - if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) return -EFAULT; --- a/mm/mremap.c~revert-mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/mm/mremap.c @@ -545,7 +545,7 @@ static unsigned long move_vma(struct vm_ if (moved_len < old_len) { err = -ENOMEM; } else if (vma->vm_ops && vma->vm_ops->mremap) { - err = vma->vm_ops->mremap(new_vma, flags); + err = vma->vm_ops->mremap(new_vma); } if (unlikely(err)) { _