From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f177.google.com (mail-pd0-f177.google.com [209.85.192.177]) by kanga.kvack.org (Postfix) with ESMTP id 1E1676B0033 for ; Wed, 25 Sep 2013 13:44:46 -0400 (EDT) Received: by mail-pd0-f177.google.com with SMTP id y10so6323550pdj.8 for ; Wed, 25 Sep 2013 10:44:45 -0700 (PDT) Received: by mail-bk0-f44.google.com with SMTP id mz10so13bkb.3 for ; Wed, 25 Sep 2013 10:44:42 -0700 (PDT) Date: Wed, 25 Sep 2013 19:44:36 +0200 From: Ingo Molnar Subject: Re: mm: insure topdown mmap chooses addresses above security minimum Message-ID: <20130925174436.GA14037@gmail.com> References: <1380057811-5352-1-git-send-email-timothy.c.pepper@linux.intel.com> <20130925073048.GB27960@gmail.com> <20130925171243.GA7428@tcpepper-desk.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130925171243.GA7428@tcpepper-desk.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Timothy Pepper Cc: linux-mm@kvack.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Russell King , linux-arm-kernel@lists.infradead.org, Ralf Baechle , linux-mips@linux-mips.org, Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Paul Mundt , linux-sh@vger.kernel.org, "David S. Miller" , sparclinux@vger.kernel.org, Andrew Morton , Linus Torvalds , Al Viro , James Morris , Michel Lespinasse , Rik van Riel * Timothy Pepper wrote: > On Wed 25 Sep at 09:30:49 +0200 mingo@kernel.org said: > > > info.flags = VM_UNMAPPED_AREA_TOPDOWN; > > > info.length = len; > > > - info.low_limit = PAGE_SIZE; > > > + info.low_limit = max(PAGE_SIZE, PAGE_ALIGN(mmap_min_addr)); > > > info.high_limit = mm->mmap_base; > > > info.align_mask = filp ? get_align_mask() : 0; > > > info.align_offset = pgoff << PAGE_SHIFT; > > > > There appears to be a lot of repetition in these methods - instead of > > changing 6 places it would be more future-proof to first factor out the > > common bits and then to apply the fix to the shared implementation. > > Besides that existing redundancy in the multiple somewhat similar > arch_get_unmapped_area_topdown() functions, I was expecting people might > question the added redundancy of the six instances of: > > max(PAGE_SIZE, PAGE_ALIGN(mmap_min_addr)); That redundancy would be automatically addressed by my suggestion. Thanks, Ingo -- 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