From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753598AbaENDgX (ORCPT ); Tue, 13 May 2014 23:36:23 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:33106 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752914AbaENDgU (ORCPT ); Tue, 13 May 2014 23:36:20 -0400 From: Sasha Levin To: linux-mm@kvack.org Cc: kirill.shutemov@linux.intel.com, davej@redhat.com, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, peterz@infradead.org, mingo@kernel.org, Sasha Levin Subject: [PATCH] mm: remap_file_pages: grab file ref to prevent race while mmaping Date: Tue, 13 May 2014 23:35:42 -0400 Message-Id: <1400038542-9705-1-git-send-email-sasha.levin@oracle.com> X-Mailer: git-send-email 1.9.1 X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A file reference should be held while a file is mmaped, otherwise it might be freed while being used. Suggested-by: Hugh Dickins Signed-off-by: Sasha Levin --- mm/mmap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index 2a0e0a8..da3c212 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2593,6 +2593,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, struct vm_area_struct *vma; unsigned long populate = 0; unsigned long ret = -EINVAL; + struct file *file; pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. " "See Documentation/vm/remap_file_pages.txt.\n", @@ -2636,8 +2637,10 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, munlock_vma_pages_range(vma, start, start + size); } + file = get_file(vma->vm_file); ret = do_mmap_pgoff(vma->vm_file, start, size, prot, flags, pgoff, &populate); + fput(file); out: up_write(&mm->mmap_sem); if (populate) -- 1.7.10.4