Subject: Re: IPv4/IPv6 sysctl unregistration deadlock

From: Patrick McHardy <[email-masked]>
Date: Mon, 02 Mar 2009 23:20:49 +0100

Ben Greear wrote:
> With both of Stephen's patches included in the latest -rc6 source,
> I re-ran the test and it seems to be working (I added printks so
> that I would know the new code was being exercise
> 
> I had 2000 or so mac-vlans configured, with 10 of them being
> re-configured concurrently, while also deleting groups of 20-100
> mac-vlans in my test.  This was locking up reliably before,
> and now it seems to be working fine.
> 
> Here's the kernel log showing the ERESTARTSYS in action.  I don't
> have an easy way to check to see if the VFS (or whatever) retried
> the call properly, but will let you all know if I see any indication
> that isn't working.
> 
> I only saw the ipv6 fixup in my logs, but maybe my test case just
> doesn't hit the other...

This looks like its working fine. Despite the non-desirable active
spinning, this seems like the best fix (actually much simpler than
I expected to be possible) at this time. If we just could avoid
the spinning when unnecessary, it would be perfect :)