In case we hit a failure condition in vmbus_process_offer() and a rescind offer
was pending for the channel we just do free_channel() so
CHANNELMSG_RELID_RELEASED
will never be send to the host. We have to follow vmbus_process_rescind_offer()
path anyway.
To support the change we need to protect list_del in
vmbus_process_rescind_offer()
hitting an uninitialized list.
Reported-by: Dexuan Cui <de...@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
---
drivers/hv/channel_mgmt.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index eb9ce94..fdccd16 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -152,6 +152,7 @@ static struct vmbus_channel *alloc_channel(void)
spin_lock_init(&channel->inbound_lock);
spin_lock_init(&channel->lock);
+ INIT_LIST_HEAD(&channel->listentry);
INIT_LIST_HEAD(&channel->sc_list);
INIT_LIST_HEAD(&channel->percpu_list);
@@ -308,6 +309,7 @@ static void vmbus_process_offer(struct work_struct *work)
struct vmbus_channel *channel;
bool fnew = true;
bool enq = false;
+ bool failure = false;
int ret;
unsigned long flags;
@@ -408,19 +410,33 @@ static void vmbus_process_offer(struct work_struct *work)
spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
list_del(&newchannel->listentry);
spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
+ /*
+ * Init listentry again as vmbus_process_rescind_offer can try
+ * doing list_del again.
+ */
+ INIT_LIST_HEAD(&channel->listentry);
kfree(newchannel->device_obj);
+ newchannel->device_obj = NULL;
goto err_free_chan;
}
+ goto done_init_rescind;
+err_free_chan:
+ failure = true;
done_init_rescind:
+ /*
+ * Get additional reference as vmbus_put_channel() can be called
+ * either directly or through vmbus_process_rescind_offer().
+ */
+ vmbus_get_channel(newchannel);
spin_lock_irqsave(&newchannel->lock, flags);
/* The next possible work is rescind handling */
INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
/* Check if rescind offer was already received */
if (newchannel->rescind)
queue_work(newchannel->controlwq, &newchannel->work);
+ else if (failure)
+ vmbus_put_channel(newchannel);
spin_unlock_irqrestore(&newchannel->lock, flags);
- return;
-err_free_chan:
vmbus_put_channel(newchannel);
}
--
1.9.3
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