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Re: possible bug in net/tc35815.c in linux-2.6.19

To: Jeff Garzik <jeff@garzik.org>
Subject: Re: possible bug in net/tc35815.c in linux-2.6.19
From: Ralf Baechle <ralf@linux-mips.org>
Date: Mon, 26 Feb 2007 10:26:59 +0000
Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>, Philip Guo <pg@cs.stanford.edu>, ahennessy@mvista.com, netdev@vger.kernel.org, linux-mips@linux-mips.org, Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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References: <45DFEC09.3020801@cs.stanford.edu> <45E031A3.806@googlemail.com> <45E0B651.2050601@garzik.org>
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On Sat, Feb 24, 2007 at 05:04:01PM -0500, Jeff Garzik wrote:

> >>I am a graduate student working on finding bugs in Linux drivers using
> >>an automated research tool.  I think I've found a possible bug in
> >>net/tc35815.c, and I'd appreciate it if you could confirm/disconfirm it.
> >>
> >>Thanks,
> >>Philip
> >>
> >>---
> >>net/tc35815.c
> >>
> >>tc35815_driver is never unregistered in tc35815_cleanup_module()
> >>
> >>static int __init tc35815_init_module(void)
> >>{
> >>    return pci_register_driver(&tc35815_driver);
> >>}
> >>
> >>static void __exit tc35815_cleanup_module(void)
> >>{
> >>    struct net_device *next_dev;
> >>
> >>    while (root_tc35815_dev) {
> >>        struct net_device *dev = root_tc35815_dev;
> >>        next_dev = ((struct tc35815_local *)dev->priv)->next_module;
> >>        iounmap((void *)(dev->base_addr));
> >>        unregister_netdev(dev);
> >>        free_netdev(dev);
> >>        root_tc35815_dev = next_dev;
> >>    }
> >>}
> >>
> >>
> >
> >I think that you are right, but I don't know this code.
> >
> >Jeff, what do you think about this?
> >
> >Regards,
> >Michal
> 
> I created my own patch for this (and one other bug), and checked it in.
> 
> Really, though, someone in MIPS-land should give this driver some loving 
> care.  It is filled with bugs and 2.4-era anachronisms.

Took a look at it.  It's sort of a non-bug because the driver cannot be
compiled as module, so the module_exit function cannot possibly be
executed.  The board support code is calling into the driver which makes
it impossible to build this driver as a module, yet it's possible to
select building this driver as a module ...  Oh yeah, that root_tc35815_dev
stuff is also pretty ugly.

Atsushi?

  Ralf

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