This is a request for merge of upstream commit 4a658527271b ("xen-netback:
delete NAPI instance when queue fails to initialize") on v4.4.y tree.
If 'xenvif_connect()' fails after successful 'netif_napi_add()', the napi is
not cleaned up. Because 'create_queues()' frees the queues in its error
handling code, if the 'xenvif_free()' is called for the vif, use-after-free
occurs. The upstream commit fixes the problem by cleaning up the napi in the
'xenvif_connect()'.
Attaching the original patch below for your convenience.
Tested-by: Markus Boehme <markubo@xxxxxxxxx>
Thanks,
SeongJae Park
==================================== >8 =======================================
>From 4a658527271bce43afb1cf4feec89afe6716ca59 Mon Sep 17 00:00:00 2001
From: David Vrabel <david.vrabel@xxxxxxxxxx>
Date: Fri, 15 Jan 2016 14:55:35 +0000
Subject: [PATCH] xen-netback: delete NAPI instance when queue fails to
initialize
When xenvif_connect() fails it may leave a stale NAPI instance added to
the device. Make sure we delete it in the error path.
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
---
drivers/net/xen-netback/interface.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index e7bd63eb2876..3bba6ceee132 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -615,6 +615,7 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
queue->tx_irq = 0;
err_unmap:
xenvif_unmap_frontend_rings(queue);
+ netif_napi_del(&queue->napi);
err:
module_put(THIS_MODULE);
return err;
--
2.17.1
