The patch below does not apply to the 4.20-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5cbab6303b4791a3e6713dfe2c5fda6a867f9adc Mon Sep 17 00:00:00 2001
From: Raju Rangoju rajur@chelsio.com Date: Thu, 3 Jan 2019 23:05:31 +0530 Subject: [PATCH] nvmet-rdma: fix null dereference under heavy load
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 Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Raju Rangoju rajur@chelsio.com Signed-off-by: Sagi Grimberg sagi@grimberg.me Signed-off-by: Jens Axboe axboe@kernel.dk
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c index a8d23eb80192..a884e3a0e8af 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; + + 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; }