VisionFive2 Linux kernel

StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)

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author: Casey Chen <cachen@purestorage.com> 2021-07-07 14:14:31 -0700 committer: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 2021-07-31 08:13:46 +0200 commit: f11bec89ad63aa4b23df5c62713e17075701ab19 parent: b34c668a867ffdcf8bd8db4a36512572e82b4a15
Commit Summary:
nvme-pci: fix multiple races in nvme_setup_io_queues
Diffstat:
1 file changed, 56 insertions, 8 deletions
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index fb1c5ae0da39..d963f25fc7ae 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1562,6 +1562,28 @@ static void nvme_init_queue(struct nvme_queue *nvmeq, u16 qid)
 	wmb(); /* ensure the first interrupt sees the initialization */
 }
 
+/*
+ * Try getting shutdown_lock while setting up IO queues.
+ */
+static int nvme_setup_io_queues_trylock(struct nvme_dev *dev)
+{
+	/*
+	 * Give up if the lock is being held by nvme_dev_disable.
+	 */
+	if (!mutex_trylock(&dev->shutdown_lock))
+		return -ENODEV;
+
+	/*
+	 * Controller is in wrong state, fail early.
+	 */
+	if (dev->ctrl.state != NVME_CTRL_CONNECTING) {
+		mutex_unlock(&dev->shutdown_lock);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 static int nvme_create_queue(struct nvme_queue *nvmeq, int qid, bool polled)
 {
 	struct nvme_dev *dev = nvmeq->dev;
@@ -1590,8 +1612,11 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid, bool polled)
 		goto release_cq;
 
 	nvmeq->cq_vector = vector;
-	nvme_init_queue(nvmeq, qid);
 
+	result = nvme_setup_io_queues_trylock(dev);
+	if (result)
+		return result;
+	nvme_init_queue(nvmeq, qid);
 	if (!polled) {
 		result = queue_request_irq(nvmeq);
 		if (result < 0)
@@ -1599,10 +1624,12 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid, bool polled)
 	}
 
 	set_bit(NVMEQ_ENABLED, &nvmeq->flags);
+	mutex_unlock(&dev->shutdown_lock);
 	return result;
 
 release_sq:
 	dev->online_queues--;
+	mutex_unlock(&dev->shutdown_lock);
 	adapter_delete_sq(dev, qid);
 release_cq:
 	adapter_delete_cq(dev, qid);
@@ -2176,7 +2203,18 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	if (nr_io_queues == 0)
 		return 0;
 
-	clear_bit(NVMEQ_ENABLED, &adminq->flags);
+	/*
+	 * Free IRQ resources as soon as NVMEQ_ENABLED bit transitions
+	 * from set to unset. If there is a window to it is truely freed,
+	 * pci_free_irq_vectors() jumping into this window will crash.
+	 * And take lock to avoid racing with pci_free_irq_vectors() in
+	 * nvme_dev_disable() path.
+	 */
+	result = nvme_setup_io_queues_trylock(dev);
+	if (result)
+		return result;
+	if (test_and_clear_bit(NVMEQ_ENABLED, &adminq->flags))
+		pci_free_irq(pdev, 0, adminq);
 
 	if (dev->cmb_use_sqes) {
 		result = nvme_cmb_qdepth(dev, nr_io_queues,
@@ -2192,14 +2230,17 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 		result = nvme_remap_bar(dev, size);
 		if (!result)
 			break;
-		if (!--nr_io_queues)
-			return -ENOMEM;
+		if (!--nr_io_queues) {
+			result = -ENOMEM;
+			goto out_unlock;
+		}
 	} while (1);
 	adminq->q_db = dev->dbs;
 
  retry:
 	/* Deregister the admin queue's interrupt */
-	pci_free_irq(pdev, 0, adminq);
+	if (test_and_clear_bit(NVMEQ_ENABLED, &adminq->flags))
+		pci_free_irq(pdev, 0, adminq);
 
 	/*
 	 * If we enable msix early due to not intx, disable it again before
@@ -2208,8 +2249,10 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	pci_free_irq_vectors(pdev);
 
 	result = nvme_setup_irqs(dev, nr_io_queues);
-	if (result <= 0)
-		return -EIO;
+	if (result <= 0) {
+		result = -EIO;
+		goto out_unlock;
+	}
 
 	dev->num_vecs = result;
 	result = max(result - 1, 1);
@@ -2223,8 +2266,9 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	 */
 	result = queue_request_irq(adminq);
 	if (result)
-		return result;
+		goto out_unlock;
 	set_bit(NVMEQ_ENABLED, &adminq->flags);
+	mutex_unlock(&dev->shutdown_lock);
 
 	result = nvme_create_io_queues(dev);
 	if (result || dev->online_queues < 2)
@@ -2233,6 +2277,9 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	if (dev->online_queues - 1 < dev->max_qid) {
 		nr_io_queues = dev->online_queues - 1;
 		nvme_disable_io_queues(dev);
+		result = nvme_setup_io_queues_trylock(dev);
+		if (result)
+			return result;
 		nvme_suspend_io_queues(dev);
 		goto retry;
 	}
@@ -2241,6 +2288,9 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 					dev->io_queues[HCTX_TYPE_READ],
 					dev->io_queues[HCTX_TYPE_POLL]);
 	return 0;
+out_unlock:
+	mutex_unlock(&dev->shutdown_lock);
+	return result;
 }
 
 static void nvme_del_queue_end(struct request *req, blk_status_t error)