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SubjectRe: [PATCH v2] uio: Fix uio driver to refcount device
Responding to myself ...

On 13/03/15 10:17, Brian Russell wrote:
> Protect uio driver from crashing if its owner is hot unplugged while there
> are open fds.
>
> Signed-off-by: Brian Russell <brussell@brocade.com>
> ---
> drivers/uio/uio.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
> index 6276f13..70ce015 100644
> --- a/drivers/uio/uio.c
> +++ b/drivers/uio/uio.c
> @@ -434,9 +434,11 @@ static int uio_open(struct inode *inode, struct file *filep)
> goto out;
> }
>
> + get_device(idev);
> +

This is bogus, idev is uio_device *, not device *. Turns out this patch only masked the crash I was seeing, so please ignore. Updated version to follow ...

Thanks,

Brian

> if (!try_module_get(idev->owner)) {
> ret = -ENODEV;
> - goto out;
> + goto err_module_get;
> }
>
> listener = kmalloc(sizeof(*listener), GFP_KERNEL);
> @@ -462,6 +464,9 @@ err_infoopen:
> err_alloc_listener:
> module_put(idev->owner);
>
> +err_module_get:
> + put_device(idev);
> +
> out:
> return ret;
> }
> @@ -485,6 +490,7 @@ static int uio_release(struct inode *inode, struct file *filep)
>
> module_put(idev->owner);
> kfree(listener);
> + put_device(idev);
> return ret;
> }
>
>


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