2023-09-08 07:04:18

by Xuan Zhuo

[permalink] [raw]
Subject: Re: [PATCH v2] virtio-mmio: fix memory leak of vm_dev

On Thu, 7 Sep 2023 14:17:16 +0000, Maximilian Heyne <[email protected]> wrote:
> With the recent removal of vm_dev from devres its memory is only freed
> via the callback virtio_mmio_release_dev. However, this only takes
> effect after device_add is called by register_virtio_device. Until then
> it's an unmanaged resource and must be explicitly freed on error exit.
>
> This bug was discovered and resolved using Coverity Static Analysis
> Security Testing (SAST) by Synopsys, Inc.
>
> Cc: <[email protected]>
> Fixes: 55c91fedd03d ("virtio-mmio: don't break lifecycle of vm_dev")
> Signed-off-by: Maximilian Heyne <[email protected]>

Reviewed-by: Xuan Zhuo <[email protected]>

> ---
> drivers/virtio/virtio_mmio.c | 19 ++++++++++++++-----
> 1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 97760f611295..59892a31cf76 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -631,14 +631,17 @@ static int virtio_mmio_probe(struct platform_device *pdev)
> spin_lock_init(&vm_dev->lock);
>
> vm_dev->base = devm_platform_ioremap_resource(pdev, 0);
> - if (IS_ERR(vm_dev->base))
> - return PTR_ERR(vm_dev->base);
> + if (IS_ERR(vm_dev->base)) {
> + rc = PTR_ERR(vm_dev->base);
> + goto free_vm_dev;
> + }
>
> /* Check magic value */
> magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
> if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
> dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
> - return -ENODEV;
> + rc = -ENODEV;
> + goto free_vm_dev;
> }
>
> /* Check device version */
> @@ -646,7 +649,8 @@ static int virtio_mmio_probe(struct platform_device *pdev)
> if (vm_dev->version < 1 || vm_dev->version > 2) {
> dev_err(&pdev->dev, "Version %ld not supported!\n",
> vm_dev->version);
> - return -ENXIO;
> + rc = -ENXIO;
> + goto free_vm_dev;
> }
>
> vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
> @@ -655,7 +659,8 @@ static int virtio_mmio_probe(struct platform_device *pdev)
> * virtio-mmio device with an ID 0 is a (dummy) placeholder
> * with no function. End probing now with no error reported.
> */
> - return -ENODEV;
> + rc = -ENODEV;
> + goto free_vm_dev;
> }
> vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
>
> @@ -685,6 +690,10 @@ static int virtio_mmio_probe(struct platform_device *pdev)
> put_device(&vm_dev->vdev.dev);
>
> return rc;
> +
> +free_vm_dev:
> + kfree(vm_dev);
> + return rc;
> }
>
> static int virtio_mmio_remove(struct platform_device *pdev)
> --
> 2.40.1
>
>
>
>
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