On Sat, Nov 30, 2013 at 08:48:35PM -0800, Greg KH wrote:

On Thu, Nov 28, 2013 at 12:48:09PM +0000, Wei Liu wrote:

quoted

With the introduction of "xen-netback: Don't destroy the netdev until
the vif is shut down" (upstream commit id 279f438e36), vif disconnect
and free are separated. However in the backported verion reference
counting code was not correctly modified, and the reset of vif->tx_irq
was lost. If frontend goes through vif life cycle more than once the
reference counting is skewed.

This patch adds back the missing tx_irq reset line. It also moves
several lines of the reference counting code to vif_free, so the moved
code corresponds to the counterpart in vif_alloc, thus the reference
counting is balanced.

3.12 and onward versions are not affected by this bug, because reference
counting code was removed due to the introduction of 1:1 model.

This pacth should be backported to all stable verions which are lower
than 3.12 and have 279f438e36.

What stable versions are those?  279f438e36 showed up in 3.12-rc2, and
was not marked for stable inclusion, so what kernel would end up needing
this patch?

Greg,

279f438e36 was backported to at least stable branches 

  3.11.y: [off-list ref] commit id f495ddc46
  3.10.y: [off-list ref] commit id a4626bf64

So at least those two need this patch.

And I remeber 3.8.y.z extended stable branch maintained by Kamal also
has the said commit.

confused,

Sorry, I should've stated cleared all versions.

BTW the above patch applies to 3.11.y. I can provide backports to 3.10.y
as well, if necessary.

Wei.

greg k-h