| From | Greg Kroah-Hartman <> | Subject | [ 127/150] ppp: set qdisc_tx_busylock to avoid LOCKDEP splat | Date | Tue, 26 Feb 2013 15:56:24 -0800 |
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3.8-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
[ 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 <yaneti@declera.com> Tested-by: Yanko Kaneti <yaneti@declera.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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,
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