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author | Sean Hefty <sean.hefty@intel.com> | 2012-04-25 17:42:35 (GMT) |
---|---|---|
committer | Roland Dreier <roland@purestorage.com> | 2012-05-08 18:17:34 (GMT) |
commit | b6cec8aa4a799d1e146095f0ba52454710f5ede4 (patch) | |
tree | 784c2ed70e9900ee90bf788e51d76c1b15767b3a /drivers/infiniband/core/cma.c | |
parent | 5909ce545db415ae8c26e849df862e8cc1acf571 (diff) | |
download | linux-fsl-qoriq-b6cec8aa4a799d1e146095f0ba52454710f5ede4.tar.xz |
RDMA/cma: Fix lockdep false positive recursive locking
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>
Diffstat (limited to 'drivers/infiniband/core/cma.c')
-rw-r--r-- | drivers/infiniband/core/cma.c | 42 |
1 files changed, 22 insertions, 20 deletions
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index e3e470f..79c7eeb 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -1218,13 +1218,13 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event) } if (!conn_id) { ret = -ENOMEM; - goto out; + goto err1; } mutex_lock_nested(&conn_id->handler_mutex, SINGLE_DEPTH_NESTING); ret = cma_acquire_dev(conn_id); if (ret) - goto release_conn_id; + goto err2; conn_id->cm_id.ib = cm_id; cm_id->context = conn_id; @@ -1236,31 +1236,33 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event) */ atomic_inc(&conn_id->refcount); ret = conn_id->id.event_handler(&conn_id->id, &event); - if (!ret) { - /* - * Acquire mutex to prevent user executing rdma_destroy_id() - * while we're accessing the cm_id. - */ - mutex_lock(&lock); - if (cma_comp(conn_id, RDMA_CM_CONNECT) && (conn_id->id.qp_type != IB_QPT_UD)) - ib_send_cm_mra(cm_id, CMA_CM_MRA_SETTING, NULL, 0); - mutex_unlock(&lock); - mutex_unlock(&conn_id->handler_mutex); - cma_deref_id(conn_id); - goto out; - } + if (ret) + goto err3; + + /* + * Acquire mutex to prevent user executing rdma_destroy_id() + * while we're accessing the cm_id. + */ + mutex_lock(&lock); + if (cma_comp(conn_id, RDMA_CM_CONNECT) && (conn_id->id.qp_type != IB_QPT_UD)) + ib_send_cm_mra(cm_id, CMA_CM_MRA_SETTING, NULL, 0); + mutex_unlock(&lock); + mutex_unlock(&conn_id->handler_mutex); + mutex_unlock(&listen_id->handler_mutex); cma_deref_id(conn_id); + return 0; +err3: + cma_deref_id(conn_id); /* Destroy the CM ID by returning a non-zero value. */ conn_id->cm_id.ib = NULL; - -release_conn_id: +err2: cma_exch(conn_id, RDMA_CM_DESTROYING); mutex_unlock(&conn_id->handler_mutex); - rdma_destroy_id(&conn_id->id); - -out: +err1: mutex_unlock(&listen_id->handler_mutex); + if (conn_id) + rdma_destroy_id(&conn_id->id); return ret; } |