linux/drivers/infiniband/ulp/ipoib
Haggai Eran 8b7cce0dae IB/ipoib: Prevent lockdep warning in __ipoib_ib_dev_flush
__ipoib_ib_dev_flush calls itself recursively on child devices, and lockdep
complains about locking vlan_rwsem twice (see below). Use down_read_nested
instead of down_read to prevent the warning.

 =============================================
 [ INFO: possible recursive locking detected ]
 4.1.0-rc4+ #36 Tainted: G           O
 ---------------------------------------------
 kworker/u20:2/261 is trying to acquire lock:
  (&priv->vlan_rwsem){.+.+..}, at: [<ffffffffa0791e2a>] __ipoib_ib_dev_flush+0x3a/0x2b0 [ib_ipoib]

 but task is already holding lock:
  (&priv->vlan_rwsem){.+.+..}, at: [<ffffffffa0791e2a>] __ipoib_ib_dev_flush+0x3a/0x2b0 [ib_ipoib]

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&priv->vlan_rwsem);
   lock(&priv->vlan_rwsem);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 3 locks held by kworker/u20:2/261:
  #0:  ("%s""ipoib_flush"){.+.+..}, at: [<ffffffff810827cc>] process_one_work+0x15c/0x760
  #1:  ((&priv->flush_heavy)){+.+...}, at: [<ffffffff810827cc>] process_one_work+0x15c/0x760
  #2:  (&priv->vlan_rwsem){.+.+..}, at: [<ffffffffa0791e2a>] __ipoib_ib_dev_flush+0x3a/0x2b0 [ib_ipoib]

 stack backtrace:
 CPU: 3 PID: 261 Comm: kworker/u20:2 Tainted: G           O    4.1.0-rc4+ #36
 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007
 Workqueue: ipoib_flush ipoib_ib_dev_flush_heavy [ib_ipoib]
  ffff8801c6c54790 ffff8801c9927af8 ffffffff81665238 0000000000000001
  ffffffff825b5b30 ffff8801c9927bd8 ffffffff810bba51 ffff880100000000
  ffffffff00000001 ffff880100000001 ffff8801c6c55428 ffff8801c6c54790
 Call Trace:
  [<ffffffff81665238>] dump_stack+0x4f/0x6f
  [<ffffffff810bba51>] __lock_acquire+0x741/0x1820
  [<ffffffff810bcbf8>] lock_acquire+0xc8/0x240
  [<ffffffffa0791e2a>] ? __ipoib_ib_dev_flush+0x3a/0x2b0 [ib_ipoib]
  [<ffffffff81669d2c>] down_read+0x4c/0x70
  [<ffffffffa0791e2a>] ? __ipoib_ib_dev_flush+0x3a/0x2b0 [ib_ipoib]
  [<ffffffffa0791e2a>] __ipoib_ib_dev_flush+0x3a/0x2b0 [ib_ipoib]
  [<ffffffffa0791e4a>] __ipoib_ib_dev_flush+0x5a/0x2b0 [ib_ipoib]
  [<ffffffffa07920ba>] ipoib_ib_dev_flush_heavy+0x1a/0x20 [ib_ipoib]
  [<ffffffff81082871>] process_one_work+0x201/0x760
  [<ffffffff810827cc>] ? process_one_work+0x15c/0x760
  [<ffffffff81082ef0>] worker_thread+0x120/0x4d0
  [<ffffffff81082dd0>] ? process_one_work+0x760/0x760
  [<ffffffff81082dd0>] ? process_one_work+0x760/0x760
  [<ffffffff81088b7e>] kthread+0xfe/0x120
  [<ffffffff81088a80>] ? __init_kthread_worker+0x70/0x70
  [<ffffffff8166c6e2>] ret_from_fork+0x42/0x70
  [<ffffffff81088a80>] ? __init_kthread_worker+0x70/0x70

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2015-07-14 13:20:12 -04:00
..
ipoib_cm.c IPoIB/CM: Fix indentation level 2015-05-05 13:21:27 -04:00
ipoib_ethtool.c net: get rid of SET_ETHTOOL_OPS 2014-05-13 17:43:20 -04:00
ipoib_fs.c IPoIB: Remove unnecessary test for NULL before debugfs_remove() 2014-08-12 21:59:54 -07:00
ipoib_ib.c IB/ipoib: Prevent lockdep warning in __ipoib_ib_dev_flush 2015-07-14 13:20:12 -04:00
ipoib_main.c IB/IPoIB: Fix bad error flow in ipoib_add_port() 2015-07-14 13:20:10 -04:00
ipoib_multicast.c IB/ipoib: Remove IPOIB_MCAST_RUN bit 2015-04-15 16:06:19 -04:00
ipoib_netlink.c infiniband: make sure the src net is infiniband when create new link 2014-01-03 20:38:56 -05:00
ipoib_verbs.c IB/core: Change ib_create_cq to use struct ib_cq_init_attr 2015-06-12 14:49:10 -04:00
ipoib_vlan.c IB/ipoib: Fix ndo_get_iflink 2015-04-17 15:21:04 -04:00
ipoib.h IB/ipoib: Remove IPOIB_MCAST_RUN bit 2015-04-15 16:06:19 -04:00
Kconfig kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT 2011-01-20 17:02:05 -08:00
Makefile IB/ipoib: Add rtnl_link_ops support 2012-09-20 16:49:17 -04:00