[PATCH v2] nvme-pci: fix dbbuf_sq_db point to freed memory

[Lulina (A)]

The case is that nvme device support NVME_CTRL_OACS_DBBUF_SUPP, and
return failed when the driver sent nvme_admin_dbbuf. The nvmeq->dbbuf_sq_db
point to freed memory, as nvme_dbbuf_set is called after nvme_dbbuf_init.

Signed-off-by: lulina <lina.lul...@huawei.com>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index c33bb20..a477905 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -251,16 +251,25 @@ static int nvme_dbbuf_dma_alloc(struct nvme_dev *dev)
 static void nvme_dbbuf_dma_free(struct nvme_dev *dev)
 {
        unsigned int mem_size = nvme_dbbuf_size(dev->db_stride);
+       unsigned int i;
 
        if (dev->dbbuf_dbs) {
                dma_free_coherent(dev->dev, mem_size,
                                  dev->dbbuf_dbs, dev->dbbuf_dbs_dma_addr);
                dev->dbbuf_dbs = NULL;
+               for (i = dev->ctrl.queue_count - 1; i > 0; i--) {
+                       dev->queues[i].dbbuf_sq_db = NULL;
+                       dev->queues[i].dbbuf_cq_db = NULL;
+               }
        }
        if (dev->dbbuf_eis) {
                dma_free_coherent(dev->dev, mem_size,
                                  dev->dbbuf_eis, dev->dbbuf_eis_dma_addr);
                dev->dbbuf_eis = NULL;
+               for (i = dev->ctrl.queue_count - 1; i > 0; i--) {
+                       dev->queues[i].dbbuf_sq_ei = NULL;
+                       dev->queues[i].dbbuf_cq_ei = NULL;
+               }
        }
 }
 
-- 
1.8.3.1