From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f51.google.com (mail-ee0-f51.google.com [74.125.83.51]) by kanga.kvack.org (Postfix) with ESMTP id 0DB4F6B0036 for ; Wed, 14 May 2014 05:18:23 -0400 (EDT) Received: by mail-ee0-f51.google.com with SMTP id e51so1144507eek.10 for ; Wed, 14 May 2014 02:18:23 -0700 (PDT) Received: from jenni2.inet.fi (mta-out1.inet.fi. [62.71.2.199]) by mx.google.com with ESMTP id n46si1176560eeo.247.2014.05.14.02.18.21 for ; Wed, 14 May 2014 02:18:22 -0700 (PDT) Date: Wed, 14 May 2014 12:15:46 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCH] mm: remap_file_pages: grab file ref to prevent race while mmaping Message-ID: <20140514091546.GA29388@node.dhcp.inet.fi> References: <1400038542-9705-1-git-send-email-sasha.levin@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1400038542-9705-1-git-send-email-sasha.levin@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Sasha Levin Cc: linux-mm@kvack.org, kirill.shutemov@linux.intel.com, davej@redhat.com, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, peterz@infradead.org, mingo@kernel.org On Tue, May 13, 2014 at 11:35:42PM -0400, Sasha Levin wrote: > 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 Sorry, again. :-/ Acked-by: Kirill A. Shutemov > --- > 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 from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Kirill A. Shutemov -- 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