From: Steven Whitehouse (terhi.victor@logonet.com)
Date: Fri Oct 11 2002 - 17:56:23 EEST
Hi,
>
> On Fri, Oct 11, 2002 at 02:47:36PM +0100, Steven Whitehouse wrote:
>
> > > I yesterday published my changes to redo the /proc files for AX.25,
> > > NET/ROM and ROSE with the seq_file stuff. As usually these changesets
> > > are available at http://linux-ham.bkbits.net/linux-2.5.
> > >
> > > 73 de DO1GRB op Ralf
> >
> > It seems you beat me to it :-) though there is one extra thing that still needs
> > to be fixed in the uid code from my patch where ax25_findbyuid() returns
> > a pointer to a structure which might disappear at any time. Its only use
> > is to check permissions at bind time, so I just moved the check under
> > the lock,
>
> Unfortunately the code is full of such funnies. Remember as the code is
> in 2.5 there are no more locks outside protecting us from our own thread
> safety - or rather the lack thereof. In particular the socket locking
> is rather hard to get right.
>
Yes I know, I worked on this for DECnet a while back :-) My plan since I am
rather constrained by time was to start at the lower levels of this
and do one small easily testable feature as I get time to work on it
and very slowly work towards the higher layers.
> Another problem we still have - and we're sharing it with other protocols
> such ipv4 - is that our proc code is holding a lock for the time the
> /proc file is open. That's not a significant time but it may delay
> access, so I've made most of those loads rw locks. Worst case a buggy
> or malicious piece of software might even hold a proc file open for a long
> time thereby stalling the functioning of the stack partially or fully.
>
Its only during read operations, not the open that the lock is held I
think, but I agree that an rw lock is the best solution here.
> If you could update your fix I certainly would accept it :)
>
> 73 de DO1GRB op Ralf
>
Ok. I'll do that,
Steve.
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