8b7cce0dae
__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> |
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