From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: TUN problems (regression?) Date: Thu, 20 Dec 2012 15:50:01 -0800 Message-ID: <20121220155001.538bbdb0@nehalam.linuxnetplumber.net> References: <4151394.nMo40zlg68@sifl> <1356046697.21834.3606.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Paul Moore , Jason Wang , netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from mail.vyatta.com ([76.74.103.46]:37042 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750776Ab2LTXvR (ORCPT ); Thu, 20 Dec 2012 18:51:17 -0500 In-Reply-To: <1356046697.21834.3606.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 20 Dec 2012 15:38:17 -0800 Eric Dumazet wrote: > On Thu, 2012-12-20 at 18:16 -0500, Paul Moore wrote: > > [CC'ing netdev in case this is a known problem I just missed ...] > > > > Hi Jason, > > > > I started doing some more testing with the multiqueue TUN changes and I ran > > into a problem when running tunctl: running it once w/o arguments works as > > expected, but running it a second time results in failure and a > > kmem_cache_sanity_check() failure. The problem appears to be very repeatable > > on my test VM and happens independent of the LSM/SELinux fixup patches. > > > > Have you seen this before? > > > > Obviously code in tun_flow_init() is wrong... > > static int tun_flow_init(struct tun_struct *tun) > { > int i; > > tun->flow_cache = kmem_cache_create("tun_flow_cache", > sizeof(struct tun_flow_entry), 0, 0, > NULL); > if (!tun->flow_cache) > return -ENOMEM; > ... > } > > > I have no idea why we would need a kmem_cache per tun_struct, > and why we even need a kmem_cache. Normally flow malloc/free should be good enough. It might make sense to use private kmem_cache if doing hlist_nulls. Acked-by: Stephen Hemminger