b6cec8aa4a
The following lockdep problem was reported by Or Gerlitz <ogerlitz@mellanox.com>: [ INFO: possible recursive locking detected ] 3.3.0-32035-g1b2649e-dirty #4 Not tainted --------------------------------------------- kworker/5:1/418 is trying to acquire lock: (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0138a41>] rdma_destroy_i d+0x33/0x1f0 [rdma_cm] but task is already holding lock: (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0135130>] cma_disable_ca llback+0x24/0x45 [rdma_cm] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&id_priv->handler_mutex); lock(&id_priv->handler_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by kworker/5:1/418: #0: (ib_cm){.+.+.+}, at: [<ffffffff81042ac1>] process_one_work+0x210/0x4a 6 #1: ((&(&work->work)->work)){+.+.+.}, at: [<ffffffff81042ac1>] process_on e_work+0x210/0x4a6 #2: (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0135130>] cma_disab le_callback+0x24/0x45 [rdma_cm] stack backtrace: Pid: 418, comm: kworker/5:1 Not tainted 3.3.0-32035-g1b2649e-dirty #4 Call Trace: [<ffffffff8102b0fb>] ? console_unlock+0x1f4/0x204 [<ffffffff81068771>] __lock_acquire+0x16b5/0x174e [<ffffffff8106461f>] ? save_trace+0x3f/0xb3 [<ffffffff810688fa>] lock_acquire+0xf0/0x116 [<ffffffffa0138a41>] ? rdma_destroy_id+0x33/0x1f0 [rdma_cm] [<ffffffff81364351>] mutex_lock_nested+0x64/0x2ce [<ffffffffa0138a41>] ? rdma_destroy_id+0x33/0x1f0 [rdma_cm] [<ffffffff81065a78>] ? trace_hardirqs_on_caller+0x11e/0x155 [<ffffffff81065abc>] ? trace_hardirqs_on+0xd/0xf [<ffffffffa0138a41>] rdma_destroy_id+0x33/0x1f0 [rdma_cm] [<ffffffffa0139c02>] cma_req_handler+0x418/0x644 [rdma_cm] [<ffffffffa012ee88>] cm_process_work+0x32/0x119 [ib_cm] [<ffffffffa0130299>] cm_req_handler+0x928/0x982 [ib_cm] [<ffffffffa01302f3>] ? cm_req_handler+0x982/0x982 [ib_cm] [<ffffffffa0130326>] cm_work_handler+0x33/0xfe5 [ib_cm] [<ffffffff81065a78>] ? trace_hardirqs_on_caller+0x11e/0x155 [<ffffffffa01302f3>] ? cm_req_handler+0x982/0x982 [ib_cm] [<ffffffff81042b6e>] process_one_work+0x2bd/0x4a6 [<ffffffff81042ac1>] ? process_one_work+0x210/0x4a6 [<ffffffff813669f3>] ? _raw_spin_unlock_irq+0x2b/0x40 [<ffffffff8104316e>] worker_thread+0x1d6/0x350 [<ffffffff81042f98>] ? rescuer_thread+0x241/0x241 [<ffffffff81046a32>] kthread+0x84/0x8c [<ffffffff8136e854>] kernel_thread_helper+0x4/0x10 [<ffffffff81366d59>] ? retint_restore_args+0xe/0xe [<ffffffff810469ae>] ? __init_kthread_worker+0x56/0x56 [<ffffffff8136e850>] ? gs_change+0xb/0xb The actual locking is fine, since we're dealing with different locks, but from the same lock class. cma_disable_callback() acquires the listening id mutex, whereas rdma_destroy_id() acquires the mutex for the new connection id. To fix this, delay the call to rdma_destroy_id() until we've released the listening id mutex. Signed-off-by: Sean Hefty <sean.hefty@intel.com> Signed-off-by: Roland Dreier <roland@purestorage.com> |
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