[PATCH] [2.4] [2.5] Fix PPPoATM crash on disconnection

PPPoATM uses tasklet_disable() on a tasklet inside a struct and then
frees the struct, leaving a pointer to the freed tasklet inside tasklet
lists.

This patch replaces tasklet_disable() with tasklet_kill().

net/atm/pppoatm.c

@@ -125,7 +125,7 @@ static void pppoatm_unassign_vcc(struct atm_vcc *atmvcc)
 	pvcc = atmvcc_to_pvcc(atmvcc);
 	atmvcc->push = pvcc->old_push;
 	atmvcc->pop = pvcc->old_pop;
-	tasklet_disable(&pvcc->wakeup_tasklet);
+	tasklet_kill(&pvcc->wakeup_tasklet);
 	ppp_unregister_channel(&pvcc->chan);
 	atmvcc->user_back = NULL;
 	kfree(pvcc);