Subject: Re: [Bugme-new] [Bug 7962] New: oops in port_carrier_check

From: Jarek Poplawski <[email-masked]>
Date: Fri, 9 Feb 2007 08:42:11 +0100

On 07-02-2007 23:09, Stephen Hemminger wrote:
> On Wed, 7 Feb 2007 12:52:16 -0800
> Andrew Morton <[email-masked]> wrote:
...
>> Feb  7 21:20:18 plop kernel: BUG: unable to handle kernel paging request at
>> virtual address 6b6b6b6b
>> Feb  7 21:20:18 plop kernel:  printing eip:
>> Feb  7 21:20:18 plop kernel: *pde = 00000000
>> Feb  7 21:20:18 plop kernel: Oops: 0000 [#1]
>> Feb  7 21:20:18 plop kernel: CPU:    0
>> Feb  7 21:20:19 plop kernel: EIP:    0060:[pg0+814360305/1067136000]    Not
>> tainted VLI
>> Feb  7 21:20:19 plop kernel: EIP:    0060:[<f0eed6f1>]    Not tainted VLI
>> Feb  7 21:20:19 plop kernel: EFLAGS: 00010202   (2.6.20.0.rc7-1mdv #1)
>> Feb  7 21:20:19 plop kernel: EIP is at port_carrier_check+0x22/0x75 [bridge]
>> Feb  7 21:20:19 plop kernel: eax: 6b6b6b6b   ebx: 6b6b6b6b   ecx: 00000000  

I think it's caused by pending delayed workqueue
trying to use dev after kfree (POISON_FREE in eax, ebx). 

> static void port_carrier_check(struct work_struct *work)
> {
>        struct net_bridge_port *p;
>        struct net_device *dev;
>        struct net_bridge *br;
>
>        dev = container_of(work, struct net_bridge_port,
>                           carrier_check.work)->dev;
>        work_release(work);
>
>        rtnl_lock();
>        p = dev->br_port;
>        if (!p)
>                goto done;
>        br = p->br;
>
>        if (netif_carrier_ok(dev))
>                p->path_cost = port_cost(dev);
>
>        if (br->dev->flags & IFF_UP) {

My investigation seems to point at this line (p == ebx
but not NULL because of mem debugging on, probably).

Regards,
Jarek P.