There is a dead lock in usnic ib_register and netdev_notify path. usnic_ib_discover_pf() | mutex_lock(&usnic_ib_ibdev_list_lock); | usnic_ib_device_add(); | ib_register_device() | usnic_ib_query_port() | mutex_lock(&us_ibdev->usdev_lock); | ib_get_eth_speed() | rtnl_lock() order of lock: &usnic_ib_ibdev_list_lock -> usdev_lock -> rtnl_lock rtnl_lock() | usnic_ib_netdevice_event() | mutex_lock(&usnic_ib_ibdev_list_lock); order of lock: rtnl_lock -> &usnic_ib_ibdev_list_lock Solution is to use ib_device_get_by_netdev() to lookup ib_dev while handling netdev/ inet events. Signed-off-by: Parvi Kaustubhi <pkaustub@xxxxxxxxx> Reviewed-by: Govindarajulu Varadarajan <gvaradar@xxxxxxxxx> Reviewed-by: Tanmay Inamdar <tinamdar@xxxxxxxxx> --- Changelog: v2->v3: * Jason: drivers should not hold any locks while calling ib_unregister_device() * Jason: use https://github.com/jgunthorpe/linux/commits/device_locking_cleanup v1->v2: * Have notifier blocks in usnic_ib_dev instead of using workqueue to defer event handling. --- drivers/infiniband/hw/usnic/usnic_ib_main.c | 34 ++++++++++++++--------------- 1 file changed, 16 insertions(+), 18 deletions(-) diff --git a/drivers/infiniband/hw/usnic/usnic_ib_main.c b/drivers/infiniband/hw/usnic/usnic_ib_main.c index 9529a08..53d6c12 100644 --- a/drivers/infiniband/hw/usnic/usnic_ib_main.c +++ b/drivers/infiniband/hw/usnic/usnic_ib_main.c @@ -216,18 +216,17 @@ static int usnic_ib_netdevice_event(struct notifier_block *notifier, unsigned long event, void *ptr) { struct usnic_ib_dev *us_ibdev; + struct ib_device *ibdev; struct net_device *netdev = netdev_notifier_info_to_dev(ptr); - mutex_lock(&usnic_ib_ibdev_list_lock); - list_for_each_entry(us_ibdev, &usnic_ib_ibdev_list, ib_dev_link) { - if (us_ibdev->netdev == netdev) { - usnic_ib_handle_usdev_event(us_ibdev, event); - break; - } - } - mutex_unlock(&usnic_ib_ibdev_list_lock); - + ibdev = ib_device_get_by_netdev(netdev, RDMA_DRIVER_USNIC); + if (!ibdev) + goto exit; + else + us_ibdev = container_of(ibdev, struct usnic_ib_dev, ib_dev); + usnic_ib_handle_usdev_event(us_ibdev, event); +exit: return NOTIFY_DONE; } @@ -282,16 +281,15 @@ static int usnic_ib_inetaddr_event(struct notifier_block *notifier, struct usnic_ib_dev *us_ibdev; struct in_ifaddr *ifa = ptr; struct net_device *netdev = ifa->ifa_dev->dev; + struct ib_device *ibdev; - mutex_lock(&usnic_ib_ibdev_list_lock); - list_for_each_entry(us_ibdev, &usnic_ib_ibdev_list, ib_dev_link) { - if (us_ibdev->netdev == netdev) { - usnic_ib_handle_inet_event(us_ibdev, event, ptr); - break; - } - } - mutex_unlock(&usnic_ib_ibdev_list_lock); - + ibdev = ib_device_get_by_netdev(netdev, RDMA_DRIVER_USNIC); + if (!ibdev) + goto exit; + else + us_ibdev = container_of(ibdev, struct usnic_ib_dev, ib_dev); + usnic_ib_handle_inet_event(us_ibdev, event, ptr); +exit: return NOTIFY_DONE; } static struct notifier_block usnic_ib_inetaddr_notifier = { -- 2.7.0
