Re: [PATCH] hwrng: virtio - fix copy_data() handling of partial reads

[Herbert Xu <herbert@gondor.apana.org.au>]

On Thu, Nov 05, 2026 at 03:17:33PM +0800, Xiang Lei wrote:
> vi->data_avail is decremented on each read, so it holds the remaining
> bytes rather than the total length. Subtracting vi->data_idx from it
> again in commit e3046eeada29 ("hwrng: virtio: clamp device-reported
> used.len at copy_data()") undercounts the bytes left after a partial
> read. This can leave vi->data_avail nonzero without queuing a new
> request, causing virtio_read() to hang on have_data.
> 
> Clamp vi->data_avail to sizeof(vi->data) - vi->data_idx instead.
> 
> Fixes: e3046eeada29 ("hwrng: virtio: clamp device-reported used.len at copy_data()")
> Tested-by: Wei Liu <liuwei@kylinos.cn>
> Cc: stable@vger.kernel.org
> Signed-off-by: Xiang Lei <leixiang@kylinos.cn>
> ---
>  drivers/char/hw_random/virtio-rng.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
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