I thought about this some more, and I realize we can just always take the vlan_mutex after the RTNL rather than having to add another delayed work item or anything like that. So I queued up the patch below -- the issue you found causes a clear lockdep warning, and this patch fixes that for me, so I'm confident this fixes the problem.
--- IPoIB: Fix deadlock between ipoib_open() and child interface create Fix a deadlock between child interface creation/deletion and ipoib start/stop. The former takes vlan_mutex, and then might take RTNL via register_netdev()/unregister_netdev(). The latter is executed with RTNL held, and tries to take vlan_mutex, which can lead to an AB-BA deadlock. Fix this by having the child interface creation/deletion code take the RTNL first so vlan_mutex always nests inside RTNL. We can use register_netdevice() for child interfaces because we form the interface name from the parent interface and hence don't need the '%' expansion of register_netdev(). Reported-by: Yossi Etigin <[email protected]> Signed-off-by: Roland Dreier <[email protected]> --- drivers/infiniband/ulp/ipoib/ipoib_vlan.c | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c index 2cf1a40..5a76a55 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c @@ -61,6 +61,7 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) ppriv = netdev_priv(pdev); + rtnl_lock(); mutex_lock(&ppriv->vlan_mutex); /* @@ -111,7 +112,7 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) goto device_init_failed; } - result = register_netdev(priv->dev); + result = register_netdevice(priv->dev); if (result) { ipoib_warn(priv, "failed to initialize; error %i", result); goto register_failed; @@ -134,12 +135,13 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) list_add_tail(&priv->list, &ppriv->child_intfs); mutex_unlock(&ppriv->vlan_mutex); + rtnl_unlock(); return 0; sysfs_failed: ipoib_delete_debug_files(priv->dev); - unregister_netdev(priv->dev); + unregister_netdevice(priv->dev); register_failed: ipoib_dev_cleanup(priv->dev); @@ -149,6 +151,7 @@ device_init_failed: err: mutex_unlock(&ppriv->vlan_mutex); + rtnl_unlock(); return result; } @@ -162,10 +165,11 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey) ppriv = netdev_priv(pdev); + rtnl_lock(); mutex_lock(&ppriv->vlan_mutex); list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) { if (priv->pkey == pkey) { - unregister_netdev(priv->dev); + unregister_netdevice(priv->dev); ipoib_dev_cleanup(priv->dev); list_del(&priv->list); free_netdev(priv->dev); @@ -175,6 +179,7 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey) } } mutex_unlock(&ppriv->vlan_mutex); + rtnl_unlock(); return ret; } -- 1.6.0.4 _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
