Re: [PATCH] virtio/vhost-user: Fix wrong vhost notifier GPtrArray size

["Alex Bennée" <alex.bennee@linaro.org>]

Yajun Wu <yajunw@nvidia.com> writes:

> In fetch_or_create_notifier, idx begins with 0. So the GPtrArray size
> should be idx + 1 and g_ptr_array_set_size should be called with idx + 1.
>
> This wrong GPtrArray size causes fetch_or_create_notifier return an invalid
> address. Passing this invalid pointer to vhost_user_host_notifier_remove
> causes assert fail:
>
>     qemu/include/qemu/int128.h:27: int128_get64: Assertion `r == a' failed.
> 	shutting down, reason=crashed
>
> Backends like dpdk-vdpa which sends out vhost notifier requests almost always
> hit qemu crash.

My bad. I was looking for ways to exercise this code but the internal
tests didn't do it. I guess I should look at getting a test setup for
dpdk. Anyway:

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>


>
> Fixes: 503e355465 ("virtio/vhost-user: dynamically assign VhostUserHostNotifiers")
> Signed-off-by: Yajun Wu <yajunw@nvidia.com>
> Acked-by: Parav Pandit <parav@nvidia.com>
> Change-Id: I87e0f7591ca9a59d210879b260704a2d9e9d6bcd
> ---
>  hw/virtio/vhost-user.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index b040c1ad2b..dbc690d16c 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -1525,7 +1525,7 @@ static VhostUserHostNotifier *fetch_or_create_notifier(VhostUserState *u,
>  {
>      VhostUserHostNotifier *n = NULL;
>      if (idx >= u->notifiers->len) {
> -        g_ptr_array_set_size(u->notifiers, idx);
> +        g_ptr_array_set_size(u->notifiers, idx + 1);
>      }
>  
>      n = g_ptr_array_index(u->notifiers, idx);


-- 
Alex Bennée