Delay QP destroy completion until all siw references to QP are
dropped. The calling RDMA core will free QP structure after
successful return from siw_qp_destroy() call, so siw must not
hold any remaining reference to the QP upon return.
A use-after-free was encountered in xfstest generic/460, while
testing NFSoRDMA. Here, after a TCP connection drop by peer,
the triggered siw_cm_work_handler got delayed until after
QP destroy call, referencing a QP which has already freed.
Fixes: 303ae1cdfdf7 ("rdma/siw: application interface")
Reported-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
Signed-off-by: Bernard Metzler <bmt@xxxxxxxxxxxxxx>
---
drivers/infiniband/sw/siw/siw.h | 1 +
drivers/infiniband/sw/siw/siw_qp.c | 2 +-
drivers/infiniband/sw/siw/siw_verbs.c | 3 +++
3 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/sw/siw/siw.h b/drivers/infiniband/sw/siw/siw.h
index df03d84c6868..2f3a9cda3850 100644
--- a/drivers/infiniband/sw/siw/siw.h
+++ b/drivers/infiniband/sw/siw/siw.h
@@ -418,6 +418,7 @@ struct siw_qp {
struct ib_qp base_qp;
struct siw_device *sdev;
struct kref ref;
+ struct completion qp_free;
struct list_head devq;
int tx_cpu;
struct siw_qp_attrs attrs;
diff --git a/drivers/infiniband/sw/siw/siw_qp.c b/drivers/infiniband/sw/siw/siw_qp.c
index 7e01f2438afc..e6f634971228 100644
--- a/drivers/infiniband/sw/siw/siw_qp.c
+++ b/drivers/infiniband/sw/siw/siw_qp.c
@@ -1342,6 +1342,6 @@ void siw_free_qp(struct kref *ref)
vfree(qp->orq);
siw_put_tx_cpu(qp->tx_cpu);
-
+ complete(&qp->qp_free);
atomic_dec(&sdev->num_qp);
}
diff --git a/drivers/infiniband/sw/siw/siw_verbs.c b/drivers/infiniband/sw/siw/siw_verbs.c
index 8dedae7ae79e..3e814cfb298c 100644
--- a/drivers/infiniband/sw/siw/siw_verbs.c
+++ b/drivers/infiniband/sw/siw/siw_verbs.c
@@ -480,6 +480,8 @@ int siw_create_qp(struct ib_qp *ibqp, struct ib_qp_init_attr *attrs,
list_add_tail(&qp->devq, &sdev->qp_list);
spin_unlock_irqrestore(&sdev->lock, flags);
+ init_completion(&qp->qp_free);
+
return 0;
err_out_xa:
@@ -624,6 +626,7 @@ int siw_destroy_qp(struct ib_qp *base_qp, struct ib_udata *udata)
qp->scq = qp->rcq = NULL;
siw_qp_put(qp);
+ wait_for_completion(&qp->qp_free);
return 0;
}
--
2.32.0
