From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id 0C9526B0007 for ; Mon, 29 Jan 2018 13:28:15 -0500 (EST) Received: by mail-wr0-f200.google.com with SMTP id a63so6342472wrc.15 for ; Mon, 29 Jan 2018 10:28:15 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id y8sor6142936edb.5.2018.01.29.10.28.13 for (Google Transport Security); Mon, 29 Jan 2018 10:28:13 -0800 (PST) Date: Mon, 29 Jan 2018 21:28:11 +0300 From: "Kirill A. Shutemov" Subject: Re: [netfilter-core] kernel panic: Out of memory and no killable processes... (2) Message-ID: <20180129182811.fze4vrb5zd5cojmr@node.shutemov.name> References: <001a1144b0caee2e8c0563d9de0a@google.com> <201801290020.w0T0KK8V015938@www262.sakura.ne.jp> <20180129072357.GD5906@breakpoint.cc> <20180129082649.sysf57wlp7i7ltb2@node.shutemov.name> <20180129165722.GF5906@breakpoint.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180129165722.GF5906@breakpoint.cc> Sender: owner-linux-mm@kvack.org List-ID: To: Florian Westphal Cc: Tetsuo Handa , davem@davemloft.net, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, aarcange@redhat.com, yang.s@alibaba-inc.com, mhocko@suse.com, syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org, mingo@kernel.org, linux-mm@kvack.org, rientjes@google.com, akpm@linux-foundation.org, guro@fb.com, kirill.shutemov@linux.intel.com On Mon, Jan 29, 2018 at 05:57:22PM +0100, Florian Westphal wrote: > Kirill A. Shutemov wrote: > > On Mon, Jan 29, 2018 at 08:23:57AM +0100, Florian Westphal wrote: > > > > vmalloc() once became killable by commit 5d17a73a2ebeb8d1 ("vmalloc: back > > > > off when the current task is killed") but then became unkillable by commit > > > > b8c8a338f75e052d ("Revert "vmalloc: back off when the current task is > > > > killed""). Therefore, we can't handle this problem from MM side. > > > > Please consider adding some limit from networking side. > > > > > > I don't know what "some limit" would be. I would prefer if there was > > > a way to supress OOM Killer in first place so we can just -ENOMEM user. > > > > Just supressing OOM kill is a bad idea. We still leave a way to allocate > > arbitrary large buffer in kernel. > > Isn't that what we do everywhere in network stack? > > I think we should try to allocate whatever amount of memory is needed > for the given xtables ruleset, given that is what admin requested us to do. Is it correct that "admin" in this case is root in random container? I mean, can we get access to it with CLONE_NEWUSER|CLONE_NEWNET? This can be fun. > I also would not know what limit is sane -- I've seen setups with as much > as 100k iptables rules, and that was 5 years ago. > > And even if we add a "Xk rules" limit, it might be too much for > low-memory systems, or not enough for whatever other use case there > might be. I hate what I'm saying, but I guess we need some tunable here. Not sure what exactly. -- 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