On Mon, 31 Oct 2016 16:11:41 +0100 Maarten ter Huurne <maarten@xxxxxxxxxxxxxx> wrote:
> check_sync() calls bucket_find_contain(), which in turn calls
> dma_get_max_seg_size(), which dereferences the device pointer.
>
> ...
>
> --- a/lib/dma-debug.c
> +++ b/lib/dma-debug.c
> @@ -1223,6 +1223,11 @@ static void check_sync(struct device *dev,
> struct hash_bucket *bucket;
> unsigned long flags;
>
> + if (!ref->dev) {
> + err_printk(dev, NULL, "DMA-API: device driver passes NULL for device to DMA sync function; cannot check usage\n");
> + return;
> + }
> +
> bucket = get_hash_bucket(ref, &flags);
>
> entry = bucket_find_contain(&bucket, ref, &flags);
Well.
a) who is calling check_sync() without having filled in ref.dev?
How does this occur? Is this a bug in the caller?
b) why does check_sync() have a `dev' argument anyway? Is there any
situation in which that will differ from ref.dev?
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