[Xen-devel] [PATCHv3 1/6] evtchn: clear xen_consumer when clearing state

[David Vrabel <david.vrabel@xxxxxxxxxx>]

Freeing a xen event channel would clear xen_consumer before clearing
the channel state, leaving a window where the channel is in a funny
state (still bound but no consumer).

Move the clear of xen_consumer into free_evtchn() where the state is
also cleared.

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
 xen/common/event_channel.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index 947880f..90e3121 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -200,6 +200,7 @@ static void free_evtchn(struct domain *d, struct evtchn 
*chn)
     /* Reset binding to vcpu0 when the channel is freed. */
     chn->state          = ECS_FREE;
     chn->notify_vcpu_id = 0;
+    chn->xen_consumer   = 0;
 
     xsm_evtchn_close_post(chn);
 }
@@ -1187,7 +1188,6 @@ void free_xen_event_channel(struct domain *d, int port)
     BUG_ON(!port_is_valid(d, port));
     chn = evtchn_from_port(d, port);
     BUG_ON(!consumer_is_xen(chn));
-    chn->xen_consumer = 0;
 
     spin_unlock(&d->event_lock);
 
@@ -1287,10 +1287,7 @@ void evtchn_destroy(struct domain *d)
 
     /* Close all existing event channels. */
     for ( i = 0; port_is_valid(d, i); i++ )
-    {
-        evtchn_from_port(d, i)->xen_consumer = 0;
         (void)__evtchn_close(d, i);
-    }
 
     /* Free all event-channel buckets. */
     spin_lock(&d->event_lock);
-- 
1.7.10.4


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