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Commit 303c07db authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ppp: set qdisc_tx_busylock to avoid LOCKDEP splat 



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: default avatarYanko Kaneti <yaneti@declera.com>
Tested-by: default avatarYanko Kaneti <yaneti@declera.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7cb08d7f

drivers/net/ppp/ppp_generic.c

+8 −0
Original line number Diff line number Diff line
@@ -1058,7 +1058,15 @@ ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64) 
	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,