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authorIgor Druzhinin <igor.druzhinin@citrix.com>2017-03-11 00:36:22 +0300
committerDavid S. Miller <davem@davemloft.net>2017-03-13 09:44:43 +0300
commitb17075d5c1988b83f840d272c795ac17d57ce804 (patch)
treeb760831992b881a42e1c3ad3990855ac8a989088 /drivers/net/xen-netback/xenbus.c
parente37791ec1ad785b59022ae211f63a16189bacebf (diff)
downloadlinux-b17075d5c1988b83f840d272c795ac17d57ce804.tar.xz
xen-netback: fix race condition on XenBus disconnect
In some cases during XenBus disconnect event handling and subsequent queue resource release there may be some TX handlers active on other processors. Use RCU in order to synchronize with them. Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/xen-netback/xenbus.c')
-rw-r--r--drivers/net/xen-netback/xenbus.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index d2d7cd9145b1..a56d3eab35dd 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -495,26 +495,26 @@ static void backend_disconnect(struct backend_info *be)
struct xenvif *vif = be->vif;
if (vif) {
+ unsigned int num_queues = vif->num_queues;
unsigned int queue_index;
- struct xenvif_queue *queues;
xen_unregister_watchers(vif);
#ifdef CONFIG_DEBUG_FS
xenvif_debugfs_delif(vif);
#endif /* CONFIG_DEBUG_FS */
xenvif_disconnect_data(vif);
- for (queue_index = 0;
- queue_index < vif->num_queues;
- ++queue_index)
- xenvif_deinit_queue(&vif->queues[queue_index]);
- spin_lock(&vif->lock);
- queues = vif->queues;
+ /* At this point some of the handlers may still be active
+ * so we need to have additional synchronization here.
+ */
vif->num_queues = 0;
- vif->queues = NULL;
- spin_unlock(&vif->lock);
+ synchronize_net();
- vfree(queues);
+ for (queue_index = 0; queue_index < num_queues; ++queue_index)
+ xenvif_deinit_queue(&vif->queues[queue_index]);
+
+ vfree(vif->queues);
+ vif->queues = NULL;
xenvif_disconnect_ctrl(vif);
}