Re: kernel NULL pointer dereference in lbs_set_11d_domain_info (3.0-rc6)

[Sven Neumann <s.neumann@raumfeld.com>]

On Tue, 2011-07-12 at 11:20 -0400, Pavel Roskin wrote:
> On 07/12/2011 03:22 AM, Sven Neumann wrote:
> > On Mon, 2011-07-11 at 17:04 -0400, Pavel Roskin wrote:
> >> On 07/11/2011 11:59 AM, Sven Neumann wrote:
> >>> Hi,
> >>>
> >>> we are using a PXA device and I am observing sporadic crashes after
> >>> resume from suspend with 3.0-rc6:
> >>>
> >>>
> >>> [ 1296.027645] PM: resume of devices complete after 296.440 msecs
> >>> [ 1296.284633] Restarting tasks ...
> >>> [ 1296.320276] done.
> >>> [ 1296.421618] mmc0: new SDIO card at address 0001
> >>> [ 1297.312570] libertas_sdio mmc0:0001:1: (unregistered net_device): 00:19:88:11:db:67, fw 9.70.7p0, cap 0x00000303
> >>
> >> I think the trouble starts with "unregistered net_device".  It looks
> >> like some structures in memory are corrupted.
> >
> > I don't think that is the problem. The output from booting the kernel
> > says "unregistered net_device" as well:
> >
> > [    9.236512] libertas_sdio: Libertas SDIO driver
> > [    9.245261] libertas_sdio: Copyright Pierre Ossman
> > [    9.762777] libertas_sdio mmc0:0001:1: (unregistered net_device):
> > 00:19:88:11:db:67, fw 9.70.7p0, cap 0x00000303
> > [    9.792377] libertas_sdio mmc0:0001:1: wlan0: Marvell WLAN 802.11
> > adapter
> 
> Oh well.  Then you need to add some tracing to 
> lbs_set_11d_domain_info().  I do it the old way.  I put this macro to 
> the beginning of the file:
> 
> #define MARK printk("%s:%d %s()\n", __FILE__, __LINE__, __func__);
> 
> And then I add "MARK" to every second line, as long as it's permitted 
> syntactically.  I may skip adding MARK where failures are unlikely, such 
> as initialization of local variables.  Once you find the line where 
> printing stops, print all variables used on that line.
> 
> I would also print the arguments as pointers in the beginning.  Maybe 
> they are corrupt.

That's what I did. The code crashes when trying to dereference the
request parameter, which is NULL. I've already sent a patch that fixes
this earlier today.


Thanks for your help,
Sven