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.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
---
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);
--
1.8.1.5
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