From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx203.postini.com [74.125.245.203]) by kanga.kvack.org (Postfix) with SMTP id 4209B6B004D for ; Fri, 20 Jan 2012 09:50:02 -0500 (EST) Date: Fri, 20 Jan 2012 08:49:57 -0600 (CST) From: Christoph Lameter Subject: Re: Hung task when calling clone() due to netfilter/slab In-Reply-To: Message-ID: References: <1326558605.19951.7.camel@lappy> <1326561043.5287.24.camel@edumazet-laptop> <1326632384.11711.3.camel@lappy> <1326648305.5287.78.camel@edumazet-laptop> <1326813630.2259.19.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1326814208.2259.21.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: "Eric W. Biederman" Cc: Eric Dumazet , Sasha Levin , Dave Jones , davem , Pekka Enberg , Matt Mackall , kaber@trash.net, pablo@netfilter.org, linux-kernel , linux-mm , netfilter-devel@vger.kernel.org, netdev On Thu, 19 Jan 2012, Eric W. Biederman wrote: > On the flip side removing from sysfs with locks held must be done > carefully, and as a default I would recommend not to hold locks over > removing things from sysfs. As removal blocks waiting for all of the > callers into sysfs those sysfs attributes to complete. > > It looks like you are ok on the removal because none of the sysfs > attributes appear to take the slub_lock, just /proc/slabinfo. But > it does look like playing with fire. Ok then I guess my last patch is needed to make sysfs operations safe. It may be good to audit the kernel for locks being held while calling sysfs functions. Isnt there a lockdep check that ensures that no locks are held? -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org