From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: [Patch net-next] netpoll: fix a rtnl lock assertion failure Date: Mon, 14 Jan 2013 10:15:43 +0100 Message-ID: <20130114091543.GA1620@minipsycho.orion> References: <1358153708-9099-1-git-send-email-amwang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, "David S. Miller" To: Cong Wang Return-path: Received: from mail-we0-f181.google.com ([74.125.82.181]:64893 "EHLO mail-we0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756580Ab3ANJPr (ORCPT ); Mon, 14 Jan 2013 04:15:47 -0500 Received: by mail-we0-f181.google.com with SMTP id t11so1906817wey.12 for ; Mon, 14 Jan 2013 01:15:46 -0800 (PST) Content-Disposition: inline In-Reply-To: <1358153708-9099-1-git-send-email-amwang@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: Mon, Jan 14, 2013 at 09:55:08AM CET, amwang@redhat.com wrote: >From: Cong Wang > >This patch fixes the following warning: > >[ 72.013864] RTNL: assertion failed at net/core/dev.c (4955) >[ 72.017758] Pid: 668, comm: netpoll-prep-v6 Not tainted 3.8.0-rc1+ #474 >[ 72.019582] Call Trace: >[ 72.020295] [] netdev_master_upper_dev_get+0x35/0x58 >[ 72.022545] [] netpoll_setup+0x61/0x340 >[ 72.024846] [] store_enabled+0x82/0xc3 >[ 72.027466] [] netconsole_target_attr_store+0x35/0x37 >[ 72.029348] [] configfs_write_file+0xe2/0x10c >[ 72.030959] [] vfs_write+0xaf/0xf6 >[ 72.032359] [] ? sysret_check+0x22/0x5d >[ 72.033824] [] sys_write+0x5c/0x84 >[ 72.035328] [] system_call_fastpath+0x16/0x1b > >by holding the rtnl_lock. And as we just want test if the device >has any upper device, so I think netdev_has_any_upper_dev() is enough. > >Cc: Jiri Pirko >Cc: David S. Miller >Signed-off-by: Cong Wang > >--- >diff --git a/net/core/netpoll.c b/net/core/netpoll.c >index 9f05067..dd28cdd 100644 >--- a/net/core/netpoll.c >+++ b/net/core/netpoll.c >@@ -1055,7 +1055,9 @@ int netpoll_setup(struct netpoll *np) > return -ENODEV; > } > >- if (netdev_master_upper_dev_get(ndev)) { >+ rtnl_lock(); >+ if (netdev_has_any_upper_dev(ndev)) { This would prevent from using dev with for example vlan dev attached to it. Is it desirable? I suppose not. Also I think in this situation, netdev_master_upper_dev_get_rcu() would be probably better to use. Not sure though. >+ rtnl_unlock(); > np_err(np, "%s is a slave device, aborting\n", np->dev_name); > err = -EBUSY; > goto put; >@@ -1066,7 +1068,6 @@ int netpoll_setup(struct netpoll *np) > > np_info(np, "device %s not up yet, forcing it\n", np->dev_name); > >- rtnl_lock(); > err = dev_open(ndev); > rtnl_unlock(); > >@@ -1094,7 +1095,8 @@ int netpoll_setup(struct netpoll *np) > np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n"); > msleep(4000); > } >- } >+ } else >+ rtnl_unlock(); > > if (!np->local_ip.ip) { > if (!np->ipv6) {