Is this a kernel bug?

Cyberman Wu
2012-11-03T08:03:29Z

Recent days we got a exception in kernel thread [kworker/n:m], but
exception handler
call do_group_exit() -> do_exit() -> schedule() and got another
exception in schedule():
/*
* If a worker is going to sleep, notify and
* ask workqueue whether it wants to wake up a
* task to maintain concurrency. If so, wake
* up the task.
*/
if (prev->flags & PF_WQ_WORKER) {
struct task_struct *to_wakeup;

to_wakeup = wq_worker_sleeping(prev, cpu);
if (to_wakeup)
try_to_wake_up_local(to_wakeup);
}

Exception occurred while wq_worker_sleeping() -> kthread_data().

It's because do_exit() -> exit_mm() -> mm_release():
/* notify parent sleeping on vfork() */
if (vfork_done) {
tsk->vfork_done = NULL;
complete(vfork_done);
}

I'm using a patched version of kernel 2.6.38.8. But I've checked code
of kernel version 3.6.5,
it seems have the same process, only with files and functions split.

--
Cyberman Wu