nvme: only add a controller to dev_list after it's been fully initialized

Without this we can easily get bad derferences on nvmeq->d_db when the nvme
kthread tries to poll the CQs for controllers that are in half initialized
state.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 30 insertions, 21 deletions

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 1f92b328522a..d82f08d671e6 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1994,6 +1994,30 @@ static void nvme_disable_io_queues(struct nvme_dev *dev)
         kthread_stop(kworker_task);
 }
 
+static int nvme_dev_list_add(struct nvme_dev *dev)
+{
+        bool start_thread = false;
+
+        spin_lock(&dev_list_lock);
+        if (list_empty(&dev_list) && IS_ERR_OR_NULL(nvme_thread)) {
+                start_thread = true;
+                nvme_thread = NULL;
+        }
+        list_add(&dev->node, &dev_list);
+        spin_unlock(&dev_list_lock);
+
+        if (start_thread) {
+                nvme_thread = kthread_run(nvme_kthread, NULL, "nvme");
+                wake_up_all(&nvme_kthread_wait);
+        } else
+                wait_event_killable(nvme_kthread_wait, nvme_thread);
+
+        if (IS_ERR_OR_NULL(nvme_thread))
+                return nvme_thread ? PTR_ERR(nvme_thread) : -EINTR;
+
+        return 0;
+}
+
 /*
 * Remove the node from the device list and check
 * for whether or not we need to stop the nvme_thread.
@@ -2109,7 +2133,6 @@ static void nvme_pci_free_ctrl(struct nvme_ctrl *ctrl)
 static void nvme_probe_work(struct work_struct *work)
 {
         struct nvme_dev *dev = container_of(work, struct nvme_dev, probe_work);
-        bool start_thread = false;
         int result;
 
         result = nvme_dev_map(dev);
@@ -2120,25 +2143,6 @@ static void nvme_probe_work(struct work_struct *work)
         if (result)
                 goto unmap;
 
-        spin_lock(&dev_list_lock);
-        if (list_empty(&dev_list) && IS_ERR_OR_NULL(nvme_thread)) {
-                start_thread = true;
-                nvme_thread = NULL;
-        }
-        list_add(&dev->node, &dev_list);
-        spin_unlock(&dev_list_lock);
-
-        if (start_thread) {
-                nvme_thread = kthread_run(nvme_kthread, NULL, "nvme");
-                wake_up_all(&nvme_kthread_wait);
-        } else
-                wait_event_killable(nvme_kthread_wait, nvme_thread);
-
-        if (IS_ERR_OR_NULL(nvme_thread)) {
-                result = nvme_thread ? PTR_ERR(nvme_thread) : -EINTR;
-                goto disable;
-        }
-
         nvme_init_queue(dev->queues[0], 0);
         result = nvme_alloc_admin_tags(dev);
         if (result)
@@ -2154,6 +2158,10 @@ static void nvme_probe_work(struct work_struct *work)
 
         dev->ctrl.event_limit = 1;
 
+        result = nvme_dev_list_add(dev);
+        if (result)
+                goto remove;
+
         /*
          * Keep the controller around but remove all namespaces if we don't have
          * any working I/O queue.
@@ -2168,6 +2176,8 @@ static void nvme_probe_work(struct work_struct *work)
 
         return;
 
+ remove:
+        nvme_dev_list_remove(dev);
  free_tags:
         nvme_dev_remove_admin(dev);
         blk_put_queue(dev->ctrl.admin_q);
@@ -2175,7 +2185,6 @@ static void nvme_probe_work(struct work_struct *work)
         dev->queues[0]->tags = NULL;
  disable:
         nvme_disable_queue(dev, 0);
-        nvme_dev_list_remove(dev);
  unmap:
         nvme_dev_unmap(dev);
  out: