Re: kern/43294: locking against myself in ioctl setting up a gre interface

[David Young <dyoung%pobox.com@localhost>]

On Sun, Nov 06, 2011 at 07:20:05PM +0000, Martin Husemann wrote:
> The following reply was made to PR kern/43294; it has been noted by GNATS.
> 
> From: Martin Husemann <martin%duskware.de@localhost>
> To: gnats-bugs%NetBSD.org@localhost
> Cc: 
> Subject: Re: kern/43294: locking against myself in ioctl setting up a gre 
> interface
> Date: Sun, 6 Nov 2011 20:18:18 +0100
> 
>  It is not possible to reporduce the panic any more, because the commands
>  given in the PR now fail:
>  
>  # ifconfig gre0 create
>  # ifconfig gre0 tunnel 10.1.1.1 10.1.2.1
>  # ifconfig gre0 192.168.170.1/30
>  ifconfig: SIOCAIFADDR: Can't assign requested address

EADDRNOTAVAIL probably comes from the socreate() call that occurs when
the interface is brought UP by assigning an address.  I think the
problem is that 10.1.1.1 is not assigned to any interface, so gre0
cannot sobind() it.  If there should be an error at all, it should be at
'ifconfig gre0 tunnel 10.1.1.1 ...'.

>  But if I then do:
>  
>  # ifconfig gre0 destroy
>  
>  I get a kernel panic:
>  
>  Mutex error: kmem_free: allocation contains active lock

I think that I have fixed this with the latest revision of sys/net/if.c.

Dave

-- 
David Young
dyoung%pobox.com@localhost    Urbana, IL    (217) 721-9981