[PATCH rdma-next] RDMA/mana_ib: drain QP references after partial table insertion

From: Leon Romanovsky <leonro@nvidia.com>

mana_table_store_ud_qp() publishes a QP at its send-queue id before
inserting the receive-queue id, dropping the XArray lock between the two
xa_insert_irq() calls. A concurrent completion handler can look up the QP
and take a transient reference. When the second insertion fails, the
rollback erased only the send-queue entry and returned, leaving both the
initial table reference and the transient reference outstanding while RDMA
core frees the QP, causing a use-after-free.

Drain the reference as normal destruction does: drop the initial reference
and wait for qp->free, releasing the QP only after every concurrent lookup
returns its reference.

Fixes: 8001e9257eca ("RDMA/mana_ib: extend mana QP table")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
Konstantin,

I saw this in one of the Sashiko runs, and I believe the AI is
correct. The reference can be acquired through the
GDMA_EQE_RNIC_QP_FATAL event.

Thanks
---
 drivers/infiniband/hw/mana/qp.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mana/qp.c b/drivers/infiniband/hw/mana/qp.c
index b5ff07e34eb7..c52f3ec14032 100644
--- a/drivers/infiniband/hw/mana/qp.c
+++ b/drivers/infiniband/hw/mana/qp.c

@@ -472,6 +472,12 @@ static void mana_table_remove_rc_qp(struct mana_ib_dev *mdev, struct mana_ib_qp
 	xa_erase_irq(&mdev->qp_table_wq, qp->ibqp.qp_num);
 }
 
+static void mana_table_drain_qp_ref(struct mana_ib_qp *qp)
+{
+	mana_put_qp_ref(qp);
+	wait_for_completion(&qp->free);
+}
+
 static int mana_table_store_ud_qp(struct mana_ib_dev *mdev, struct mana_ib_qp *qp)
 {
 	u32 qids = qp->ud_qp.queues[MANA_UD_SEND_QUEUE].id | MANA_SENDQ_MASK;

@@ -490,6 +496,7 @@ static int mana_table_store_ud_qp(struct mana_ib_dev *mdev, struct mana_ib_qp *q
 
 remove_sq:
 	xa_erase_irq(&mdev->qp_table_wq, qids);
+	mana_table_drain_qp_ref(qp);
 	return err;
 }
 

@@ -537,8 +544,7 @@ static void mana_table_remove_qp(struct mana_ib_dev *mdev,
 			  qp->ibqp.qp_type);
 		return;
 	}
-	mana_put_qp_ref(qp);
-	wait_for_completion(&qp->free);
+	mana_table_drain_qp_ref(qp);
 }
 
 static int mana_ib_create_rc_qp(struct ib_qp *ibqp, struct ib_pd *ibpd,

---
base-commit: 74f49255492a62658f36bf2578d7916f1c6ffad1
change-id: 20260721-if-mana-table-store-qp-qids-partiall-afa14f023261

Best regards,
--  
Leon Romanovsky [off-list ref]