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 <[email protected]>
Thanks,
SeongJae Park
==================================== >8 =======================================
From 4a658527271bce43afb1cf4feec89afe6716ca59 Mon Sep 17 00:00:00 2001
From: David Vrabel <[email protected]>
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 <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
---
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
On Wed, Feb 24, 2021 at 06:03:56PM +0100, SeongJae Park wrote:
> 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.
The original patch does not apply cleanly.
> Tested-by: Markus Boehme <[email protected]>
What was tested?
I backported the patch, but next time, please provide the patch that
will work properly.
greg k-h
On Wed, 24 Feb 2021 18:21:09 +0100 Greg KH <[email protected]> wrote:
> On Wed, Feb 24, 2021 at 06:03:56PM +0100, SeongJae Park wrote:
> > 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.
>
> The original patch does not apply cleanly.
I tested the commit is cleanly applicable with 'git cherry-pick' before posting
this. I just tried 'git format-patch ... && git am ...' and confirmed it
doesn't work. Sorry, my fault.
>
> > Tested-by: Markus Boehme <[email protected]>
>
> What was tested?
We confirmed the unmodified v4.4.y kernel crashes on a stress test that
repeatedly doing netdev attach/detach, while the patch applied version doesn't.
>
> I backported the patch, but next time, please provide the patch that
> will work properly.
Thanks, and apology for the inconvenience. I will do the check with posting
patch again rather than only 'git cherry-pick' from next time.
Thanks,
SeongJae Park
>
> greg k-h