vhost backend sends host notification for every VQ. If backend creates
VQs in parallel, the VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG may
arrive to QEMU in different order than incremental queue index order.
For example VQ 1's message arrive earlier than VQ 0's:
After alloc VhostUserHostNotifier for VQ 1. GPtrArray becomes
[ nil, VQ1 pointer ]
After alloc VhostUserHostNotifier for VQ 0. GPtrArray becomes
[ VQ0 pointer, nil, VQ1 pointer ]
This is wrong. fetch_notifier will return NULL for VQ 1 in
vhost_user_get_vring_base, causes host notifier miss removal(leak).
The fix is to remove current element from GPtrArray, make the right
position for element to insert.
Fixes: 503e355465 ("virtio/vhost-user: dynamically assign VhostUserHostNotifiers")
Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Parav Pandit <parav@nvidia.com>
---
hw/virtio/vhost-user.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 03415b6c95..d256ce589b 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1543,6 +1543,11 @@ static VhostUserHostNotifier *fetch_or_create_notifier(VhostUserState *u,
n = g_ptr_array_index(u->notifiers, idx);
if (!n) {
+ /*
+ * In case notification arrive out-of-order,
+ * make room for current index.
+ */
+ g_ptr_array_remove_index(u->notifiers, idx);
n = g_new0(VhostUserHostNotifier, 1);
n->idx = idx;
g_ptr_array_insert(u->notifiers, idx, n);
--
2.27.0
Yajun Wu <yajunw@nvidia.com> writes: > vhost backend sends host notification for every VQ. If backend creates > VQs in parallel, the VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG may > arrive to QEMU in different order than incremental queue index order. > > For example VQ 1's message arrive earlier than VQ 0's: > After alloc VhostUserHostNotifier for VQ 1. GPtrArray becomes > > [ nil, VQ1 pointer ] > > After alloc VhostUserHostNotifier for VQ 0. GPtrArray becomes > > [ VQ0 pointer, nil, VQ1 pointer ] > > This is wrong. fetch_notifier will return NULL for VQ 1 in > vhost_user_get_vring_base, causes host notifier miss removal(leak). > > The fix is to remove current element from GPtrArray, make the right > position for element to insert. > > Fixes: 503e355465 ("virtio/vhost-user: dynamically assign VhostUserHostNotifiers") > Signed-off-by: Yajun Wu <yajunw@nvidia.com> > Acked-by: Parav Pandit <parav@nvidia.com> > > --- > hw/virtio/vhost-user.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index 03415b6c95..d256ce589b 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -1543,6 +1543,11 @@ static VhostUserHostNotifier *fetch_or_create_notifier(VhostUserState *u, > > n = g_ptr_array_index(u->notifiers, idx); > if (!n) { > + /* > + * In case notification arrive out-of-order, > + * make room for current index. > + */ > + g_ptr_array_remove_index(u->notifiers, idx); > n = g_new0(VhostUserHostNotifier, 1); > n->idx = idx; > g_ptr_array_insert(u->notifiers, idx, n); Ahh reading the description of g_ptr_array_insert() it doesn't explicitly say it shuffles the data currently at index up but I can see from the code it does. I guess you can imply it from the other function descriptions. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> -- Alex Bennée
© 2016 - 2024 Red Hat, Inc.