Message-ID: <sashiko-outbox-198663@kernel.org>
From: sashiko-bot@kernel.org
Subject: Re: [PATCH] hwrng: virtio - fix copy_data() handling of partial
 reads
Reply-To: sashiko-reviews@lists.linux.dev
To: "Xiang Lei" <leixiang@kylinos.cn>
Cc: virtualization@lists.linux.dev, "Michael S. Tsirkin" <mst@redhat.com>, "Eugenio
 Perez" <eperezma@redhat.com>
In-Reply-To: <20261105071736.65932-1-leixiang@kylinos.cn>
References: <20261105071736.65932-1-leixiang@kylinos.cn>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Date: Thu, 05 Nov 2026 07:24:19 +0000
Precedence: list

> 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.
>=20
> Clamp vi->data_avail to sizeof(vi->data) - vi->data_idx instead.
>=20
> Fixes: e3046eeada29 ("hwrng: virtio: clamp device-reported used.len at co=
py_data()")
> Tested-by: Wei Liu <liuwei@kylinos.cn>
> Cc: stable@vger.kernel.org
> Signed-off-by: Xiang Lei <leixiang@kylinos.cn>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261105071736.6593=
2-1-leixiang@kylinos.cn?part=3D1