[2.6] ethertap and af_inet.c assertion failures

[Simon Roscic <simon.roscic@chello.at>]

(please cc me, as i´m not subscribed to lkml - thanks)

hi,

today i upgraded my kernel from 2.6.9-rc2 to 2.6.10-rc3-bk12, now i get the
following assertion failures while using the (closed source) phion vpn client,
the vpn client uses ethertap, there are no closed source kernel modules or the 
like:

KERNEL: assertion (!atomic_read(&sk->sk_wmem_alloc)) failed at 
net/ipv4/af_inet.c (150)

when the kernel prints out the above message the connection for the program 
using the vpn gets stuck - it happens very often if i use rdesktop, but it 
also happens when i just use ssh, so the bug may be triggered more often when 
there is more traffic over the vpn tunnel.

i tried with some other 2.6 kernel releases:

up to and including 2.6.9-rc2: no problem
2.6.9-rc3      does not boot on my machine
2.6.9-rc4      assertion failed as explained above
2.6.9        assertion failed as explained above

so it seems ethertap got broken somewhere post 2.6.9-rc2.
any ideas what got changed post 2.6.9-rc2 wich might cause this?

thanks for looking at this problem, if i can provide more information, just 
contact me.

bye,
 simon.