From: Jack Morgenstein Date: Thu, 21 Aug 2014 11:28:41 +0000 (+0300) Subject: IB/mlx4: Fix lockdep splat for the iboe lock X-Git-Tag: firefly_0821_release~176^2~3184^2^4~7 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=dba3ad2addcd74ec850e510f3b8a9d046cc24ef3;p=firefly-linux-kernel-4.4.55.git IB/mlx4: Fix lockdep splat for the iboe lock Chuck Lever reported the following stack trace: ================================= [ INFO: inconsistent lock state ] 3.16.0-rc2-00024-g2e78883 #17 Tainted: G E --------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. swapper/0/0 [HC0[0]:SC1[1]:HE1:SE0] takes: (&(&iboe->lock)->rlock){+.?...}, at: [] mlx4_ib_addr_event+0xdb/0x1a0 [mlx4_ib] {SOFTIRQ-ON-W} state was registered at: [] mark_irqflags+0x110/0x170 [] __lock_acquire+0x2c6/0x5b0 [] lock_acquire+0xe9/0x120 [] _raw_spin_lock+0x3e/0x80 [] mlx4_ib_scan_netdevs+0x34/0x260 [mlx4_ib] [] mlx4_ib_netdev_event+0x2b/0x40 [mlx4_ib] [] register_netdevice_notifier+0x99/0x1e0 [] mlx4_ib_add+0x743/0xbc0 [mlx4_ib] [] mlx4_add_device+0x48/0xa0 [mlx4_core] [] mlx4_register_interface+0x73/0xb0 [mlx4_core] [] cm_req_handler+0x13e/0x460 [ib_cm] [] do_one_initcall+0x112/0x1c0 [] do_init_module+0x34/0x190 [] load_module+0x5cf/0x740 [] SyS_init_module+0x99/0xd0 [] system_call_fastpath+0x16/0x1b irq event stamp: 336142 hardirqs last enabled at (336142): [] __local_bh_enable_ip+0xb5/0xc0 hardirqs last disabled at (336141): [] __local_bh_enable_ip+0x56/0xc0 softirqs last enabled at (336004): [] _local_bh_enable+0x4a/0x50 softirqs last disabled at (336005): [] irq_exit+0x44/0xd0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&iboe->lock)->rlock); lock(&(&iboe->lock)->rlock); *** DEADLOCK *** The above problem was caused by the spin lock being taken both in the process context and in a soft-irq context (in a netdev notifier handler). The required fix is to use spin_lock/unlock_bh() instead of spin_lock/unlock on the iboe lock. Reported-by: Chuck Lever Signed-off-by: Jack Morgenstein Signed-off-by: Or Gerlitz Signed-off-by: Roland Dreier --- diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c index d404a2eafa79..c231112396b2 100644 --- a/drivers/infiniband/hw/mlx4/main.c +++ b/drivers/infiniband/hw/mlx4/main.c @@ -360,7 +360,7 @@ static int eth_link_query_port(struct ib_device *ibdev, u8 port, props->state = IB_PORT_DOWN; props->phys_state = state_to_phys_state(props->state); props->active_mtu = IB_MTU_256; - spin_lock(&iboe->lock); + spin_lock_bh(&iboe->lock); ndev = iboe->netdevs[port - 1]; if (!ndev) goto out_unlock; @@ -372,7 +372,7 @@ static int eth_link_query_port(struct ib_device *ibdev, u8 port, IB_PORT_ACTIVE : IB_PORT_DOWN; props->phys_state = state_to_phys_state(props->state); out_unlock: - spin_unlock(&iboe->lock); + spin_unlock_bh(&iboe->lock); out: mlx4_free_cmd_mailbox(mdev->dev, mailbox); return err; @@ -814,11 +814,11 @@ int mlx4_ib_add_mc(struct mlx4_ib_dev *mdev, struct mlx4_ib_qp *mqp, if (!mqp->port) return 0; - spin_lock(&mdev->iboe.lock); + spin_lock_bh(&mdev->iboe.lock); ndev = mdev->iboe.netdevs[mqp->port - 1]; if (ndev) dev_hold(ndev); - spin_unlock(&mdev->iboe.lock); + spin_unlock_bh(&mdev->iboe.lock); if (ndev) { ret = 1; @@ -1265,11 +1265,11 @@ static int mlx4_ib_mcg_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid) mutex_lock(&mqp->mutex); ge = find_gid_entry(mqp, gid->raw); if (ge) { - spin_lock(&mdev->iboe.lock); + spin_lock_bh(&mdev->iboe.lock); ndev = ge->added ? mdev->iboe.netdevs[ge->port - 1] : NULL; if (ndev) dev_hold(ndev); - spin_unlock(&mdev->iboe.lock); + spin_unlock_bh(&mdev->iboe.lock); if (ndev) dev_put(ndev); list_del(&ge->list); @@ -1554,7 +1554,7 @@ static int mlx4_ib_addr_event(int event, struct net_device *event_netdev, return 0; iboe = &ibdev->iboe; - spin_lock(&iboe->lock); + spin_lock_bh(&iboe->lock); for (port = 1; port <= ibdev->dev->caps.num_ports; ++port) if ((netif_is_bond_master(real_dev) && @@ -1564,7 +1564,7 @@ static int mlx4_ib_addr_event(int event, struct net_device *event_netdev, update_gid_table(ibdev, port, gid, event == NETDEV_DOWN, 0); - spin_unlock(&iboe->lock); + spin_unlock_bh(&iboe->lock); return 0; } @@ -1742,7 +1742,7 @@ static int mlx4_ib_init_gid_table(struct mlx4_ib_dev *ibdev) } read_lock(&dev_base_lock); - spin_lock(&iboe->lock); + spin_lock_bh(&iboe->lock); for_each_netdev(&init_net, dev) { u8 port = mlx4_ib_get_dev_port(dev, ibdev); @@ -1753,7 +1753,7 @@ static int mlx4_ib_init_gid_table(struct mlx4_ib_dev *ibdev) } } - spin_unlock(&iboe->lock); + spin_unlock_bh(&iboe->lock); read_unlock(&dev_base_lock); out: return err; @@ -1770,7 +1770,7 @@ static void mlx4_ib_scan_netdevs(struct mlx4_ib_dev *ibdev, iboe = &ibdev->iboe; - spin_lock(&iboe->lock); + spin_lock_bh(&iboe->lock); mlx4_foreach_ib_transport_port(port, ibdev->dev) { enum ib_port_state port_state = IB_PORT_NOP; struct net_device *old_master = iboe->masters[port - 1]; @@ -1842,7 +1842,7 @@ static void mlx4_ib_scan_netdevs(struct mlx4_ib_dev *ibdev, } } - spin_unlock(&iboe->lock); + spin_unlock_bh(&iboe->lock); if (update_qps_port > 0) mlx4_ib_update_qps(ibdev, dev, update_qps_port);