From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yanko Kaneti , Eric Dumazet , "David S. Miller" Subject: [ 127/150] ppp: set qdisc_tx_busylock to avoid LOCKDEP splat Date: Tue, 26 Feb 2013 15:56:24 -0800 Message-Id: <20130226235537.342430443@linuxfoundation.org> In-Reply-To: <20130226235523.930663721@linuxfoundation.org> References: <20130226235523.930663721@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 303c07db487be59ae9fda10600ea65ca11c21497 ] If a qdisc is installed on a ppp device, its possible to get a lockdep splat under stress, because nested dev_queue_xmit() can lock busylock a second time (on a different device, so its a false positive) Avoid this problem using a distinct lock_class_key for ppp devices. Reported-by: Yanko Kaneti Tested-by: Yanko Kaneti Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ppp/ppp_generic.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -1058,7 +1058,15 @@ ppp_get_stats64(struct net_device *dev, return stats64; } +static struct lock_class_key ppp_tx_busylock; +static int ppp_dev_init(struct net_device *dev) +{ + dev->qdisc_tx_busylock = &ppp_tx_busylock; + return 0; +} + static const struct net_device_ops ppp_netdev_ops = { + .ndo_init = ppp_dev_init, .ndo_start_xmit = ppp_start_xmit, .ndo_do_ioctl = ppp_net_ioctl, .ndo_get_stats64 = ppp_get_stats64,