Bug caused by multicast

[Thomas Graf]

On 04/01/13 at 07:09pm, Teto wrote:
> and caused by the following code. The family and ops are correctly
> registered, I've created the multicast group beforehand. It seems it does
> work when there is a client registered in this multicast group but if there
> isn't any client, it returns -3. The return code is fine with me but I
> don't understand why there is this stack trace though.
> 
> 
> /**
> send the request
> **/
> int send_request_for_eid(u32 eid)
> {
>     //!
>     struct sk_buff *skb;
>     int rc = 0;
>     void *msg_head;
> 
>     printk( "sending request for eid %u.%u.%u.%u.\n", NIPQUAD(eid) );
> 
> 
>     /* send a message back*/
>     /* allocate some memory, since the size is not yet known use
> NLMSG_GOODSIZE*/
>     skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);

Looks like you are calling this function in (sw) interrupt context.
If you do that you will have to pass GFP_ATOMIC into genlmsg_new()
just like you would have to with kmalloc()

Sames goes for genlmsg_multicast() below.

If somehow doable I would advice you to create a worker though
and send your messages from there.