Commit e47e321a authored by Bernd Schubert's avatar Bernd Schubert Committed by Roland Dreier

RDMA/core: Fix kernel panic by always initializing qp->usecnt

We have just been investigating kernel panics related to
cq->ibcq.event_handler() completion calls.  The problem is that
ib_destroy_qp() fails with -EBUSY.

Further investigation revealed qp->usecnt is not initialized.  This
counter was introduced in linux-3.2 by commit 0e0ec7e0
("RDMA/core: Export ib_open_qp() to share XRC TGT QPs") but it only
gets initialized for IB_QPT_XRC_TGT, but it is checked in
ib_destroy_qp() for any QP type.

Fix this by initializing qp->usecnt for every QP we create.
Signed-off-by: default avatarBernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Signed-off-by: default avatarSven Breuner <sven.breuner@itwm.fraunhofer.de>

[ Initialize qp->usecnt in uverbs too.  - Sean ]
Signed-off-by: default avatarSean Hefty <sean.hefty@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
parent dcd6c922
......@@ -1485,6 +1485,7 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
qp->event_handler = attr.event_handler;
qp->qp_context = attr.qp_context;
qp->qp_type = attr.qp_type;
atomic_set(&qp->usecnt, 0);
atomic_inc(&pd->usecnt);
atomic_inc(&attr.send_cq->usecnt);
if (attr.recv_cq)
......
......@@ -421,6 +421,7 @@ struct ib_qp *ib_create_qp(struct ib_pd *pd,
qp->uobject = NULL;
qp->qp_type = qp_init_attr->qp_type;
atomic_set(&qp->usecnt, 0);
if (qp_init_attr->qp_type == IB_QPT_XRC_TGT) {
qp->event_handler = __ib_shared_qp_event_handler;
qp->qp_context = qp;
......@@ -430,7 +431,6 @@ struct ib_qp *ib_create_qp(struct ib_pd *pd,
qp->xrcd = qp_init_attr->xrcd;
atomic_inc(&qp_init_attr->xrcd->usecnt);
INIT_LIST_HEAD(&qp->open_list);
atomic_set(&qp->usecnt, 0);
real_qp = qp;
qp = __ib_open_qp(real_qp, qp_init_attr->event_handler,
......
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