On 6/24/26 17:40, Denis V. Lunev wrote: > Like tell_host(), stats_handle_request() ignores the return value of > virtqueue_add_outbuf() and kicks the queue regardless. The same "we > should always be able to add one buffer to an empty queue" assumption > does not hold once the virtqueue has been broken (e.g. on device > shutdown), where the add fails with -EIO. Unlike tell_host() it does > not wait_event() afterwards so it cannot hang, but it still kicks a > queue with nothing queued. > > Warn and bail out on failure, mirroring tell_host() and > virtballoon_free_page_report(). > > Suggested-by: David Hildenbrand <[email protected]> > Signed-off-by: Denis V. Lunev <[email protected]> > --- > drivers/virtio/virtio_balloon.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 0866a8781f0b..454bbb77331d 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -445,6 +445,7 @@ static void stats_handle_request(struct virtio_balloon > *vb) > struct virtqueue *vq; > struct scatterlist sg; > unsigned int len, num_stats; > + int err; > > num_stats = update_balloon_stats(vb); > > @@ -452,7 +453,9 @@ static void stats_handle_request(struct virtio_balloon > *vb) > if (!virtqueue_get_buf(vq, &len)) > return; > sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); > - virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); > + err = virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); > + if (WARN_ON_ONCE(err)) > + return; > virtqueue_kick(vq); > } >
Reviewed-by: David Hildenbrand (Arm) <[email protected]> Although I would just squash #4 and #5. -- Cheers, David
