Re: AX.25 in kernel 2.5 status?

From: Ralf Baechle DO1GRB (zga@greyhound.com)
Date: Fri Oct 11 2002 - 17:35:42 EEST

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    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.

    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.

    If you could update your fix I certainly would accept it :)

    73 de DO1GRB op Ralf

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