hostap 0.0.2 hangup with kernel panic when receive frame

[Jouni Malinen]

On Sun, May 18, 2003 at 04:13:19PM +0200, Litin wrote:

> Everything seems to be ok until I've connected my external antenna to the
> card. (I have no wlan device in range) imediatelly after card receive any
> frame (and this will be probably beacon frame because it doesn't matter if I
> set or not set iwconfig properties like channel, essid........) whole system
> hang with kernel panic message:
> 
> skput:over c28705f7:0 put:60 dev:<NULL>kernel bug at skbuff.c:92! Invalid
> operand: 0000

That error means that a skb_put() call was made to add 60 octets of data
into an skb that had an initial size of -60).. That should of course not
happen. The length of Prism2 RX and TX descriptor is 60 octets, but I
did not find any problems in skb_put() calls in the driver.

c28705f7 is an address in the function that used skb_put(). It would be
helpful if you could convert that to the function name. Since you can
apparently load the modules without crashing the system when extenral
antenna is not connected, you should be able to copy /proc/ksyms to safe
place just before crash. You can then use ksymoops or manually find the
function from that file (sort it and take the function that has a
starting address before the reported address).

If that address is in any of the Host AP drivers, it would help if you
could insmod the modules with '-m' option (insmod -m hostap.o) and save
the output to a file. This would make a more complete list of functions
in the modules (i.e., not only the exported functions).

-- 
Jouni Malinen                                            PGP id EFC895FA