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| author | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2023-06-29 15:05:26 +0300 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2023-08-10 22:24:27 +0300 |
| commit | 55c91fedd03d7b9cf0c5199b2eb12b9b8e95281a (patch) | |
| tree | af909563d6daa21555ff4bf4f8834b97c0e4e4e6 /drivers/virtio/virtio_mmio.c | |
| parent | 52a93d39b17dc7eb98b6aa3edb93943248e03b2f (diff) | |
| download | linux-55c91fedd03d7b9cf0c5199b2eb12b9b8e95281a.tar.xz | |
virtio-mmio: don't break lifecycle of vm_dev
vm_dev has a separate lifecycle because it has a 'struct device'
embedded. Thus, having a release callback for it is correct.
Allocating the vm_dev struct with devres totally breaks this protection,
though. Instead of waiting for the vm_dev release callback, the memory
is freed when the platform_device is removed. Resulting in a
use-after-free when finally the callback is to be called.
To easily see the problem, compile the kernel with
CONFIG_DEBUG_KOBJECT_RELEASE and unbind with sysfs.
The fix is easy, don't use devres in this case.
Found during my research about object lifetime problems.
Fixes: 7eb781b1bbb7 ("virtio_mmio: add cleanup for virtio_mmio_probe")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Message-Id: <20230629120526.7184-1-wsa+renesas@sang-engineering.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/virtio/virtio_mmio.c')
| -rw-r--r-- | drivers/virtio/virtio_mmio.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index a46a4a29e929..97760f611295 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -607,9 +607,8 @@ static void virtio_mmio_release_dev(struct device *_d) struct virtio_device *vdev = container_of(_d, struct virtio_device, dev); struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); - struct platform_device *pdev = vm_dev->pdev; - devm_kfree(&pdev->dev, vm_dev); + kfree(vm_dev); } /* Platform device */ @@ -620,7 +619,7 @@ static int virtio_mmio_probe(struct platform_device *pdev) unsigned long magic; int rc; - vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL); + vm_dev = kzalloc(sizeof(*vm_dev), GFP_KERNEL); if (!vm_dev) return -ENOMEM; |