Re: problems with netlink_broadcast

[Patrick McHardy <kaber@trash.net>]

Are you using GFP_ATOMIC for netlink_broadcast and alloc_skb ?

Regards,
Patrick

John Williams Floroiu wrote:
> 
> hi,
> 
> I am trying to send data to userspace from a kernel module each time a 
> kernel timer expires. so I basically call
> skb_alloc followed by netlink_broadcast.
> 
> the funny part is that if I call netlink_broadcast from the timer 
> handler (which, according to my understanding, is a
> softirq), I get a crash. on the other hand, if I dispatch a tasklet from 
> the timer handler and call skb_alloc from the
> tasklet, then I get a crash too.
> 
> the only combination that appears to work is calling skb_alloc in the 
> timer handler (pass 'skb' to the tasklet) and
> netlink_broadcast from the tasklet. this looks quite strange to me 
> because ipt_ULOG and other kernel modules doing
> similar things don't appear to hint at the existence of such 
> restrictions. could anybody figure out what could be wrong?
> 
> thanks in advance.
> 
> cheers,
> John.
>