[PATCH AUTOSEL 5.4 230/330] nvmet-rdma: fix double free of rdma queue

Sasha Levin
2020-09-18T02:59:31Z

From: Israel Rukshin <israelr@mellanox.com>

[ Upstream commit 21f9024355e58772ec5d7fc3534aa5e29d72a8b6 ]

In case rdma accept fails at nvmet_rdma_queue_connect(), release work is
scheduled. Later on, a new RDMA CM event may arrive since we didn't
destroy the cm-id and call nvmet_rdma_queue_connect_fail(), which
schedule another release work. This will cause calling
nvmet_rdma_free_queue twice. To fix this we implicitly destroy the cm_id
with non-zero ret code, which guarantees that new rdma_cm events will
not arrive afterwards. Also add a qp pointer to nvmet_rdma_queue
structure, so we can use it when the cm_id pointer is NULL or was
destroyed.

Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Suggested-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/target/rdma.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 36d906a7f70d3..b5314164479e9 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -75,6 +75,7 @@ enum nvmet_rdma_queue_state {

struct nvmet_rdma_queue {
struct rdma_cm_id *cm_id;
+ struct ib_qp *qp;
struct nvmet_port *port;
struct ib_cq *cq;
atomic_t sq_wr_avail;
@@ -464,7 +465,7 @@ static int nvmet_rdma_post_recv(struct nvmet_rdma_device *ndev,
if (ndev->srq)
ret = ib_post_srq_recv(ndev->srq, &cmd->wr, NULL);
else
- ret = ib_post_recv(cmd->queue->cm_id->qp, &cmd->wr, NULL);
+ ret = ib_post_recv(cmd->queue->qp, &cmd->wr, NULL);

if (unlikely(ret))
pr_err("post_recv cmd failed\n");
@@ -503,7 +504,7 @@ static void nvmet_rdma_release_rsp(struct nvmet_rdma_rsp *rsp)
atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);

if (rsp->n_rdma) {
- rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
+ rdma_rw_ctx_destroy(&rsp->rw, queue->qp,
queue->cm_id->port_num, rsp->req.sg,
rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
}
@@ -587,7 +588,7 @@ static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc)

WARN_ON(rsp->n_rdma <= 0);
atomic_add(rsp->n_rdma, &queue->sq_wr_avail);
- rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
+ rdma_rw_ctx_destroy(&rsp->rw, queue->qp,
queue->cm_id->port_num, rsp->req.sg,
rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
rsp->n_rdma = 0;
@@ -742,7 +743,7 @@ static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp)
}

if (nvmet_rdma_need_data_in(rsp)) {
- if (rdma_rw_ctx_post(&rsp->rw, queue->cm_id->qp,
+ if (rdma_rw_ctx_post(&rsp->rw, queue->qp,
queue->cm_id->port_num, &rsp->read_cqe, NULL))
nvmet_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
} else {
@@ -1025,6 +1026,7 @@ static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
pr_err("failed to create_qp ret= %d\n", ret);
goto err_destroy_cq;
}
+ queue->qp = queue->cm_id->qp;

atomic_set(&queue->sq_wr_avail, qp_attr.cap.max_send_wr);

@@ -1053,11 +1055,10 @@ err_destroy_cq:

static void nvmet_rdma_destroy_queue_ib(struct nvmet_rdma_queue *queue)
{
- struct ib_qp *qp = queue->cm_id->qp;
-
- ib_drain_qp(qp);
- rdma_destroy_id(queue->cm_id);
- ib_destroy_qp(qp);
+ ib_drain_qp(queue->qp);
+ if (queue->cm_id)
+ rdma_destroy_id(queue->cm_id);
+ ib_destroy_qp(queue->qp);
ib_free_cq(queue->cq);
}

@@ -1291,9 +1292,12 @@ static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,

ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
if (ret) {
- schedule_work(&queue->release_work);
- /* Destroying rdma_cm id is not needed here */
- return 0;
+ /*
+ * Don't destroy the cm_id in free path, as we implicitly
+ * destroy the cm_id here with non-zero ret code.
+ */
+ queue->cm_id = NULL;
+ goto free_queue;
}

mutex_lock(&nvmet_rdma_queue_mutex);
@@ -1302,6 +1306,8 @@ static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,

return 0;

+free_queue:
+ nvmet_rdma_free_queue(queue);
put_device:
kref_put(&ndev->ref, nvmet_rdma_free_dev);

--
2.25.1