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,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 C9A6DC2BB40 for ; Tue, 15 Dec 2020 03:27:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 855282246B for ; Tue, 15 Dec 2020 03:27:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726763AbgLOD1d (ORCPT ); Mon, 14 Dec 2020 22:27:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:36216 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726492AbgLODI4 (ORCPT ); Mon, 14 Dec 2020 22:08:56 -0500 Date: Mon, 14 Dec 2020 19:08:13 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608001695; bh=lVVw0He8RJWBqV3+ehAPPe7sH3QhSJtexexIpG7oiMY=; h=From:To:Subject:In-Reply-To:From; b=AVCOvbJq/V3lidLmIgI91yFUppDa2BxEVDwYDcg0hIc80BkqqlktSDbwCWBHjzCY6 2NedJaFT/hf/AisnoCDGieBzL2Pol4fQsz/99WYNH8+Zu9v4WymqEyjvG6UxOGIb5d cLsOekeQ1CY5FQ6+ceXB8GhYcU6PyLpo5SyTq+7M= From: Andrew Morton To: akpm@linux-foundation.org, bgeffon@google.com, catalin.marinas@arm.com, dan.carpenter@oracle.com, dan.j.williams@intel.com, dave.jiang@intel.com, dima@arista.com, hughd@google.com, jgg@ziepe.ca, jhubbard@nvidia.com, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, linux@armlinux.org.uk, luto@kernel.org, mike.kravetz@oracle.com, minchan@kernel.org, mingo@redhat.com, mm-commits@vger.kernel.org, rcampbell@nvidia.com, tglx@linutronix.de, torvalds@linux-foundation.org, tsbogend@alpha.franken.de, vbabka@suse.cz, viro@zeniv.linux.org.uk, vishal.l.verma@intel.com, will@kernel.org Subject: [patch 086/200] mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio Message-ID: <20201215030813.I8VAWZGRf%akpm@linux-foundation.org> In-Reply-To: <20201214190237.a17b70ae14f129e2dca3d204@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: Dmitry Safonov Subject: mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio As kernel expect to see only one of such mappings, any further operations on the VMA-copy may be unexpected by the kernel. Maybe it's being on the safe side, but there doesn't seem to be any expected use-case for this, so restrict it now. Link: https://lkml.kernel.org/r/20201013013416.390574-4-dima@arista.com Fixes: commit e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()") Signed-off-by: Dmitry Safonov Cc: Alexander Viro Cc: Andy Lutomirski Cc: Brian Geffon Cc: Catalin Marinas Cc: Dan Carpenter Cc: Dan Williams Cc: Dave Jiang Cc: Hugh Dickins Cc: Ingo Molnar Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Kirill A. Shutemov" Cc: Mike Kravetz Cc: Minchan Kim Cc: Ralph Campbell Cc: Russell King Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Vishal Verma Cc: Vlastimil Babka Cc: Will Deacon 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, 12 insertions(+), 5 deletions(-) --- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c~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) +static int pseudo_lock_dev_mremap(struct vm_area_struct *area, unsigned long flags) { /* Not supported */ return -EINVAL; --- a/fs/aio.c~mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/fs/aio.c @@ -324,13 +324,16 @@ static void aio_free_ring(struct kioctx } } -static int aio_ring_mremap(struct vm_area_struct *vma) +static int aio_ring_mremap(struct vm_area_struct *vma, unsigned long flags) { 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~mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/include/linux/mm.h @@ -558,7 +558,7 @@ struct vm_operations_struct { void (*open)(struct vm_area_struct * area); void (*close)(struct vm_area_struct * area); int (*split)(struct vm_area_struct * area, unsigned long addr); - int (*mremap)(struct vm_area_struct * area); + int (*mremap)(struct vm_area_struct *area, unsigned long flags); vm_fault_t (*fault)(struct vm_fault *vmf); vm_fault_t (*huge_fault)(struct vm_fault *vmf, enum page_entry_size pe_size); --- a/mm/mmap.c~mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/mm/mmap.c @@ -3405,10 +3405,14 @@ 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) +static int special_mapping_mremap(struct vm_area_struct *new_vma, + unsigned long flags) { 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~mremap-dont-allow-mremap_dontunmap-on-special_mappings-and-aio +++ a/mm/mremap.c @@ -534,7 +534,7 @@ 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); + err = vma->vm_ops->mremap(new_vma, flags); } if (unlikely(err)) { _