From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964778AbWGHLNi (ORCPT ); Sat, 8 Jul 2006 07:13:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964786AbWGHLNg (ORCPT ); Sat, 8 Jul 2006 07:13:36 -0400 Received: from rhun.apana.org.au ([64.62.148.172]:35600 "EHLO arnor.apana.org.au") by vger.kernel.org with ESMTP id S964779AbWGHLNB (ORCPT ); Sat, 8 Jul 2006 07:13:01 -0400 Date: Sat, 8 Jul 2006 21:12:40 +1000 To: Arjan van de Ven Cc: davej@redhat.com, mingo@elte.hu, akpm@osdl.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: starting mc triggers lockdep Message-ID: <20060708111240.GA7612@gondor.apana.org.au> References: <1152352400.3120.19.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1152352400.3120.19.camel@laptopd505.fenrus.org> User-Agent: Mutt/1.5.9i From: Herbert Xu Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 08, 2006 at 11:53:20AM +0200, Arjan van de Ven wrote: > > > > now for the third part, which involves the nfs client: > > > stat on an nfs file, which ends up taken the i_mutex of a directory in > > > the path (obvious), and then does > > > [] tcp_sendmsg+0x1e/0xb1a > > > [] inet_sendmsg+0x45/0x53 > > > [] sock_sendmsg+0x110/0x130 > > > [] kernel_sendmsg+0x3c/0x52 > > > [] xs_tcp_send_request+0x117/0x320 [sunrpc] > > > [] xprt_transmit+0x105/0x21e [sunrpc] > > > [] call_transmit+0x1f4/0x239 [sunrpc] > > > [] __rpc_execute+0x9b/0x1e6 [sunrpc] > > > [] rpc_execute+0x1a/0x1d [sunrpc] > > > [] rpc_call_sync+0x87/0xb9 [sunrpc] > > > [] nfs3_rpc_wrapper+0x2e/0x74 [nfs] > > > [] nfs3_proc_lookup+0xe0/0x163 [nfs] > > > where tcp_sendmsg calls lock_sock. So this is the BC dependency. > > > > This is an nfs inode. > > > > Did I miss something? > > is it not possible to nfs export /sys, and then mount it over loopback? Possibly, but not with the backtrace above. You'd need an nfs server backtrace to get the real sysfs inode. In any case, the sock lock from the other backtrace that you had (udp setsockopt) cannot be held by the kernel nfs client or server since the kernel nfs sockets are not visible to user space. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt