On Mon 5 August 2013 19:53:23 Laurent Pinchart wrote:
> The vb2_fop_mmap() function is a plug-in implementation of the mmap()
> file operation that calls vb2_mmap() on the queue associated with the
> video device. Neither the vb2_fop_mmap() function nor the v4l2_mmap()
> mmap handler in the V4L2 core take any lock, leading to race conditions
> between mmap() and other buffer-related ioctls such as VIDIOC_REQBUFS.
>
> Fix it by taking the queue or device lock around the vb2_mmap() call.
Hi Laurent,
Can you do the same for vb2_fop_get_unmapped_area()?
Thanks!
Hans
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
> ---
> drivers/media/v4l2-core/videobuf2-core.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c
> b/drivers/media/v4l2-core/videobuf2-core.c
> index 9fc4bab..bd4bade 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -2578,8 +2578,15 @@ EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf);
> int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)
> {
> struct video_device *vdev = video_devdata(file);
> + struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
> + int err;
>
> - return vb2_mmap(vdev->queue, vma);
> + if (lock && mutex_lock_interruptible(lock))
> + return -ERESTARTSYS;
> + err = vb2_mmap(vdev->queue, vma);
> + if (lock)
> + mutex_unlock(lock);
> + return err;
> }
> EXPORT_SYMBOL_GPL(vb2_fop_mmap);
>
>
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