From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx109.postini.com [74.125.245.109]) by kanga.kvack.org (Postfix) with SMTP id 8A5066B0074 for ; Wed, 14 Nov 2012 12:31:29 -0500 (EST) Received: by mail-pb0-f41.google.com with SMTP id xa7so567942pbc.14 for ; Wed, 14 Nov 2012 09:31:28 -0800 (PST) From: Joonsoo Kim Subject: [RFC PATCH] mm: WARN_ON_ONCE if f_op->mmap() change vma's start address Date: Thu, 15 Nov 2012 02:28:52 +0900 Message-Id: <1352914132-18445-1-git-send-email-js1304@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Joonsoo Kim During reviewing the source code, I found a comment which mention that after f_op->mmap(), vma's start address can be changed. I didn't verify that it is really possible, because there are so many f_op->mmap() implementation. But if there are some mmap() which change vma's start address, it is possible error situation, because we already prepare prev vma, rb_link and rb_parent and these are related to original address. So add WARN_ON_ONCE for finding that this situtation really happens. Signed-off-by: Joonsoo Kim diff --git a/mm/mmap.c b/mm/mmap.c index 2d94235..36567b7 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1333,7 +1333,11 @@ munmap_back: * * Answer: Yes, several device drivers can do it in their * f_op->mmap method. -DaveM + * Bug: If addr is changed, prev, rb_link, rb_parent should + * be updated for vma_link() */ + WARN_ON_ONCE(addr != vma->vm_start); + addr = vma->vm_start; pgoff = vma->vm_pgoff; vm_flags = vma->vm_flags; -- 1.7.9.5 -- 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