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@amazon.de

Thanks, SeongJae Park

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From 4a658527271bce43afb1cf4feec89afe6716ca59 Mon Sep 17 00:00:00 2001

From: David Vrabel david.vrabel@citrix.com 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@citrix.com Signed-off-by: David S. Miller davem@davemloft.net --- 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;