On Wed, Aug 28, 2019 at 12:37 PM Johannes Berg
<johan...@sipsolutions.net> wrote:
>
> From: Johannes Berg <johannes.b...@intel.com>
>
> If you try to make a device implementation that can handle multiple
> connections and allow disconnections (which requires overriding the
> VHOST_USER_NONE handling), then glib will warn that we remove a src
> while it's still on the mainloop, and will poll() an FD that doesn't
> exist anymore.
>
> Fix this by making vug_source_new() require pairing with the new
> vug_source_destroy() so we can keep the GSource referenced in the
> meantime.
>
> Note that this requires calling the new API in vhost-user-input.
> vhost-user-gpu also uses vug_source_new(), but never seems to free
> the result at all, so I haven't changed anything there.
>
> Fixes: 8bb7ddb78a1c ("libvhost-user: add glib source helper")
> Signed-off-by: Johannes Berg <johannes.b...@intel.com>
Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> ---
> contrib/libvhost-user/libvhost-user-glib.c | 15 ++++++++++++---
> contrib/libvhost-user/libvhost-user-glib.h | 1 +
> contrib/vhost-user-input/main.c | 6 ++----
> 3 files changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/contrib/libvhost-user/libvhost-user-glib.c
> b/contrib/libvhost-user/libvhost-user-glib.c
> index 99edd2f3de45..824c7780de61 100644
> --- a/contrib/libvhost-user/libvhost-user-glib.c
> +++ b/contrib/libvhost-user/libvhost-user-glib.c
> @@ -91,7 +91,6 @@ vug_source_new(VugDev *gdev, int fd, GIOCondition cond,
> g_source_add_poll(gsrc, &src->gfd);
> id = g_source_attach(gsrc, NULL);
> g_assert(id);
> - g_source_unref(gsrc);
>
> return gsrc;
> }
> @@ -131,6 +130,16 @@ static void vug_watch(VuDev *dev, int condition, void
> *data)
> }
> }
>
> +void vug_source_destroy(GSource *src)
> +{
> + if (!src) {
> + return;
> + }
> +
> + g_source_destroy(src);
> + g_source_unref(src);
> +}
> +
> bool
> vug_init(VugDev *dev, uint16_t max_queues, int socket,
> vu_panic_cb panic, const VuDevIface *iface)
> @@ -144,7 +153,7 @@ vug_init(VugDev *dev, uint16_t max_queues, int socket,
> }
>
> dev->fdmap = g_hash_table_new_full(NULL, NULL, NULL,
> - (GDestroyNotify) g_source_destroy);
> + (GDestroyNotify) vug_source_destroy);
>
> dev->src = vug_source_new(dev, socket, G_IO_IN, vug_watch, NULL);
>
> @@ -157,5 +166,5 @@ vug_deinit(VugDev *dev)
> g_assert(dev);
>
> g_hash_table_unref(dev->fdmap);
> - g_source_unref(dev->src);
> + vug_source_destroy(dev->src);
> }
> diff --git a/contrib/libvhost-user/libvhost-user-glib.h
> b/contrib/libvhost-user/libvhost-user-glib.h
> index 64d539d93aba..1a79a4916ef2 100644
> --- a/contrib/libvhost-user/libvhost-user-glib.h
> +++ b/contrib/libvhost-user/libvhost-user-glib.h
> @@ -31,5 +31,6 @@ void vug_deinit(VugDev *dev);
>
> GSource *vug_source_new(VugDev *dev, int fd, GIOCondition cond,
> vu_watch_cb vu_cb, gpointer data);
> +void vug_source_destroy(GSource *src);
>
> #endif /* LIBVHOST_USER_GLIB_H */
> diff --git a/contrib/vhost-user-input/main.c b/contrib/vhost-user-input/main.c
> index 449fd2171a5a..a990b3ea9e33 100644
> --- a/contrib/vhost-user-input/main.c
> +++ b/contrib/vhost-user-input/main.c
> @@ -187,7 +187,7 @@ vi_queue_set_started(VuDev *dev, int qidx, bool started)
> }
>
> if (!started && vi->evsrc) {
> - g_source_destroy(vi->evsrc);
> + vug_source_destroy(vi->evsrc);
> vi->evsrc = NULL;
> }
> }
> @@ -401,9 +401,7 @@ main(int argc, char *argv[])
>
> vug_deinit(&vi.dev);
>
> - if (vi.evsrc) {
> - g_source_unref(vi.evsrc);
> - }
> + vug_source_destroy(vi.evsrc);
> g_array_free(vi.config, TRUE);
> g_free(vi.queue);
> return 0;
> --
> 2.23.0
>
>
--
Marc-André Lureau
