From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx170.postini.com [74.125.245.170]) by kanga.kvack.org (Postfix) with SMTP id 7209E6B0371 for ; Mon, 25 Jun 2012 12:56:16 -0400 (EDT) Message-ID: <4FE89807.50708@redhat.com> Date: Mon, 25 Jun 2012 18:55:35 +0200 From: Frederic Weisbecker MIME-Version: 1.0 Subject: Re: [PATCH 11/11] protect architectures where THREAD_SIZE >= PAGE_SIZE against fork bombs References: <1340633728-12785-1-git-send-email-glommer@parallels.com> <1340633728-12785-12-git-send-email-glommer@parallels.com> In-Reply-To: <1340633728-12785-12-git-send-email-glommer@parallels.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, Frederic Weisbecker , David Rientjes , Pekka Enberg , Michal Hocko , Johannes Weiner , Christoph Lameter , devel@openvz.org, kamezawa.hiroyu@jp.fujitsu.com, Tejun Heo , Pekka Enberg , Suleiman Souhlal On 06/25/2012 04:15 PM, Glauber Costa wrote: > Because those architectures will draw their stacks directly from > the page allocator, rather than the slab cache, we can directly > pass __GFP_KMEMCG flag, and issue the corresponding free_pages. > > This code path is taken when the architecture doesn't define > CONFIG_ARCH_THREAD_INFO_ALLOCATOR (only ia64 seems to), and has > THREAD_SIZE >= PAGE_SIZE. Luckily, most - if not all - of the > remaining architectures fall in this category. > > This will guarantee that every stack page is accounted to the memcg > the process currently lives on, and will have the allocations to fail > if they go over limit. > > For the time being, I am defining a new variant of THREADINFO_GFP, not > to mess with the other path. Once the slab is also tracked by memcg, > we can get rid of that flag. > > Tested to successfully protect against :(){ :|:& };: > > Signed-off-by: Glauber Costa > CC: Christoph Lameter > CC: Pekka Enberg > CC: Michal Hocko > CC: Kamezawa Hiroyuki > CC: Johannes Weiner > CC: Suleiman Souhlal Acked-by: Frederic Weisbecker Thanks! -- 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