From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id D810F6B0036 for ; Tue, 13 May 2014 23:36:18 -0400 (EDT) Received: by mail-pa0-f54.google.com with SMTP id bj1so1108271pad.27 for ; Tue, 13 May 2014 20:36:18 -0700 (PDT) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id hb8si257142pbc.411.2014.05.13.20.36.17 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 13 May 2014 20:36:17 -0700 (PDT) From: 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> Sender: owner-linux-mm@kvack.org List-ID: 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 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 -- 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