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Commit 8a90f1a6 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Mauro Carvalho Chehab
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[media] media: vb2: Take queue or device lock in mmap-related vb2 ioctl handlers 



The vb2_fop_mmap() and vb2_fop_get_unmapped_area() functions are plug-in
implementation of the mmap() and get_unmapped_area() file operations
that calls vb2_mmap() and vb2_get_unmapped_area() on the queue
associated with the video device. Neither the
vb2_fop_mmap/vb2_fop_get_unmapped_area nor the
v4l2_mmap/vb2_get_unmapped_area functions in the V4L2 core take any
lock, leading to race conditions between mmap/get_unmapped_area and
other buffer-related ioctls such as VIDIOC_REQBUFS.
Fix it by taking the queue or device lock around the vb2_mmap() and
vb2_get_unmapped_area() calls.

Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <m.chehab@samsung.com>
parent 5548a382

drivers/media/v4l2-core/videobuf2-core.c

+16 −2
Original line number Original line Diff line number Diff line
@@ -2578,8 +2578,15 @@ EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf); 
int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)

int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)

{

{

	struct video_device *vdev = video_devdata(file);

	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);

EXPORT_SYMBOL_GPL(vb2_fop_mmap);
@@ -2685,8 +2692,15 @@ unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, 
		unsigned long len, unsigned long pgoff, unsigned long flags)

		unsigned long len, unsigned long pgoff, unsigned long flags)

{

{

	struct video_device *vdev = video_devdata(file);

	struct video_device *vdev = video_devdata(file);

	struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;

	int ret;





	return vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags);

	if (lock && mutex_lock_interruptible(lock))

		return -ERESTARTSYS;

	ret = vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags);

	if (lock)

		mutex_unlock(lock);

	return ret;

}

}

EXPORT_SYMBOL_GPL(vb2_fop_get_unmapped_area);

EXPORT_SYMBOL_GPL(vb2_fop_get_unmapped_area);

#endif

#endif