The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 228432551bd8783211e494ab35f42a4344580502 Mon Sep 17 00:00:00 2001 From: Jason Wang jasowang@redhat.com Date: Wed, 8 Jun 2022 14:14:22 +0800 Subject: [PATCH] virtio-rng: make device ready before making request
Current virtio-rng does a entropy request before DRIVER_OK, this violates the spec:
virtio spec requires that all drivers set DRIVER_OK before using devices.
Further, kernel will ignore the interrupt after commit 8b4ec69d7e09 ("virtio: harden vring IRQ").
Fixing this by making device ready before the request.
Cc: stable@vger.kernel.org Fixes: 8b4ec69d7e09 ("virtio: harden vring IRQ") Fixes: f7f510ec1957 ("virtio: An entropy device, as suggested by hpa.") Reported-and-tested-by: syzbot+5b59d6d459306a556f54@syzkaller.appspotmail.com Signed-off-by: Jason Wang jasowang@redhat.com Message-Id: 20220608061422.38437-1-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Reviewed-by: Laurent Vivier lvivier@redhat.com
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index e856df7e285c..a6f3a8a2aca6 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -159,6 +159,8 @@ static int probe_common(struct virtio_device *vdev) goto err_find; }
+ virtio_device_ready(vdev); + /* we always have a pending entropy request */ request_entropy(vi);