From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20130326173612.753687190@goodmis.org> Date: Tue, 26 Mar 2013 13:22:20 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yanko Kaneti , Eric Dumazet , "David S. Miller" Subject: [PATCH 81/86] ppp: set qdisc_tx_busylock to avoid LOCKDEP splat References: <20130326172059.136127374@goodmis.org> Content-Disposition: inline; filename=0081-ppp-set-qdisc_tx_busylock-to-avoid-LOCKDEP-splat.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6.11.1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 0b652fb68c02c1acd0307d3acac4ae7123536031 ] 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 --- drivers/net/ppp/ppp_generic.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index 5c05572..2603b99 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -1021,7 +1021,15 @@ ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) return err; } +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, }; -- 1.7.10.4