VIMAGE crashes on 9.x with hotplug net80211 devices

[Marko Zec]

On Thursday 15 November 2012 20:32:06 Hans Petter Selasky wrote:
> On Thursday 15 November 2012 20:16:12 Adrian Chadd wrote:
> > Hans brings up a very good point for USB - they split if_alloc and
> > if_attach across two different threads.

Fine, so maybe one of the following options could work:

1) pass the vnet context embedded in some other already available struct 
when forwarding request from 1st to 2nd thread; or

2) if we can safely assume that device attach events can only occur in 
context of vnet0 (and I think we can), place a few CURVNET_SET(vnet0) 
macros wherever necessary in 2nd USB "attach" thread.

> > So this works for non-USB devices, but not for USB devices.

Could you post a sample backtrace for me to look at?

> > Hans, does each device implement its own workqueue for this kind of
> > delayed action, or is there some generic work queue that is doing this
> > work?
>
> Hi,
>
> I think a new thread is created for this stuff. It is inside the USB
> subsystem, but would consider this a big *hack* to add VNET specific
> stuff in there.
>
> Isn't it possible to have curvnet return "vnet0" when nothing else is
> set?

No!  This was discussed already at several ocassions, including earlier in 
this thread: with curvnet pointing by default to vnet0, it would be 
essentially impossible to detect, trace and debug leakages between vnets.

Marko