On 1/3/2019 12:33 PM, Raju Rangoju wrote:

Under heavy load if we don't have any pre-allocated rsps left, we dynamically allocate a rsp, but we are not actually allocating memory for nvme_completion (rsp->req.rsp). In such a case, accessing pointer fields (req->rsp->status) in nvmet_req_init() will result in crash.

To fix this, allocate the memory for nvme_completion by calling nvmet_rdma_alloc_rsp()

Fixes: 8407879c("nvmet-rdma:fix possible bogus dereference under heavy load")

Cc: stable@vger.kernel.org Reviewed-by: Max Gurtovoy maxg@mellanox.com Signed-off-by: Raju Rangoju rajur@chelsio.com

-- Changes from v1:

• Moved integer to 'if' block
• Used 'unlikely' in datapath flow condition

---

drivers/nvme/target/rdma.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c index a8d23eb80192..8f9e6645fcf9 100644 --- a/drivers/nvme/target/rdma.c +++ b/drivers/nvme/target/rdma.c @@ -139,6 +139,10 @@ static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc); static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc); static void nvmet_rdma_qp_event(struct ib_event *event, void *priv); static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue); +static void nvmet_rdma_free_rsp(struct nvmet_rdma_device *ndev,

• 		struct nvmet_rdma_rsp *r);
  

+static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,

• 		struct nvmet_rdma_rsp *r);
  

static const struct nvmet_fabrics_ops nvmet_rdma_ops; @@ -182,9 +186,17 @@ nvmet_rdma_get_rsp(struct nvmet_rdma_queue *queue) spin_unlock_irqrestore(&queue->rsps_lock, flags); if (unlikely(!rsp)) {

• rsp = kmalloc(sizeof(*rsp), GFP_KERNEL);
  

• int ret = -EINVAL;
  

no real need to initialize ret variable (sorry I didn't see it in first review).

• rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
  

  if (unlikely(!rsp)) return NULL;

• ret = nvmet_rdma_alloc_rsp(queue->dev, rsp);
  

• if (unlikely(ret)) {
  

• 	kfree(rsp);
  

• 	return NULL;
  

• }
  

• rsp->allocated = true; }

@@ -197,6 +209,7 @@ nvmet_rdma_put_rsp(struct nvmet_rdma_rsp *rsp) unsigned long flags; if (unlikely(rsp->allocated)) {

• nvmet_rdma_free_rsp(rsp->queue->dev, rsp);
  

  kfree(rsp); return; }