Re: [Xen-devel] [PATCH v4 net] xen-netback: disable rogue vif in kthread context

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2014-04-01 at 16:27 -0400, David Miller wrote:
> From: Wei Liu <wei.liu2@xxxxxxxxxx>
> Date: Tue, 1 Apr 2014 12:46:12 +0100
> 
> > When netback discovers frontend is sending malformed packet it will
> > disables the interface which serves that frontend.
> > 
> > However disabling a network interface involving taking a mutex which
> > cannot be done in softirq context, so we need to defer this process to
> > kthread context.
> > 
> > This patch does the following:
> > 1. introduce a flag to indicate the interface is disabled.
> > 2. check that flag in TX path, don't do any work if it's true.
> > 3. check that flag in RX path, turn off that interface if it's true.
> > 
> > The reason to disable it in RX path is because RX uses kthread. After
> > this change the behavior of netback is still consistent -- it won't do
> > any TX work for a rogue frontend, and the interface will be eventually
> > turned off.
> > 
> > Also change a "continue" to "break" after xenvif_fatal_tx_err, as it
> > doesn't make sense to continue processing packets if frontend is rogue.
> > 
> > This is a fix for XSA-90.
> > 
> > Reported-by: TÃrÃk Edwin <edwin@xxxxxxxxxx>
> > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> 
> Applied.

Thanks.

Wei -- can you advise as to which stable trees this should be queued
for? Looks like 3.12 onwards according to
http://xenbits.xen.org/xsa/advisory-90.html which says the issue arose
between 3.11 and 3.12-rc1?

Cheers,
Ian.



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