Re: 2.6.18-mm2 - oops in cache_alloc_refill()

[Andrew Morton <akpm@osdl.org>]

On Sat, 30 Sep 2006 03:50:43 -0400
Valdis.Kletnieks@vt.edu wrote:

> On Fri, 29 Sep 2006 23:31:07 EDT, Valdis.Kletnieks@vt.edu said:
> > Fair enough,  I'm going to try reverting the 2 commits and see if things
> > behave better.
> 
> OK, it's definitely something in those 2 commits - I reverted them and the
> resulting 2.6.18-mm2 kernel has been up and stable for 4 hours, even with
> the problem gkrellm updating once a second the whole time.
> 
> I'm not *seeing* how those changes can cause trouble - unless it's this:
> 
> diff --git a/drivers/net/wireless/orinoco.c b/drivers/net/wireless/orinoco.c
> index 1840b69..9e19a96 100644
> --- a/drivers/net/wireless/orinoco.c
> +++ b/drivers/net/wireless/orinoco.c
> @@ -3037,7 +3037,7 @@ static int orinoco_ioctl_getessid(struct
>         }
>  
>         erq->flags = 1;
> -       erq->length = strlen(essidbuf) + 1;
> +       erq->length = strlen(essidbuf);

You know what the next question is ;)

Did reverting just that line fix it?

> Does some other code go batshit if length ==0? My current config doesn't
> try to actually ifup the wireless if I also have connectivity via copper (in
> order to avoid chewing up a DHCP lease in crowded address space if not needed).
> 
> % iwconfig eth5
> eth5      IEEE 802.11b  ESSID:""  Nickname:"HERMES I"
>           Mode:Managed  Frequency:2.457 GHz  Access Point: Not-Associated   
>           Bit Rate:11 Mb/s   Sensitivity:1/3  
>           Retry limit:4   RTS thr:off   Fragment thr:off
>           Power Management:off
>           Link Quality=0/92  Signal level=134/153  Noise level=134/153
>           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>           Tx excessive retries:0  Invalid misc:0   Missed beacon:0
> 
> That ESSID the source of the trouble?
> 

Might be.  I can't immediately spot a problem with it, but perhaps
length==0 causes the driver to not allocate a buffer and to then write to
the not-allocated buffer.  Not sure..