Well, I can't really comment this change because I didn't see other
changes, and I do not know what klp_kgraft_task_in_progress() means...
On 05/04, Jiri Slaby wrote:
>
> Luckily we can force the task to do that by sending it a fake signal,
But note that signal_wake_up(0) won't wake the stopped/traced tasks up.
> +static void klp_kgraft_send_fake_signal(void)
> +{
> + struct task_struct *p;
> + unsigned long flags;
> +
> + read_lock(&tasklist_lock);
> + for_each_process(p) {
Only the group leader can be klp_kgraft_task_in_progress?
Looks like you need for_each_process_thread()...
> + /*
> + * send fake signal to all non-kthread processes which are still
> + * not migrated
> + */
> + if (!(p->flags & PF_KTHREAD) &&
So this can miss the execing kernel thread, I do not know if this is
correct or not. PF_KTHREAD is cleared in flush_old_exec().
> + klp_kgraft_task_in_progress(p) &&
> + lock_task_sighand(p, &flags)) {
No need for lock_task_sighand(). Just spin_lock_irq(p->sighand->siglock).
tasklist_lock + for_each_process guarantees that "p" has a valid ->sighand.
> + signal_wake_up(p, 0);
To remind, this won't wakeup a TASK_STOPPED/TRACED thread.
> void recalc_sigpending(void)
> {
> - if (!recalc_sigpending_tsk(current) && !freezing(current))
> + if (!recalc_sigpending_tsk(current) && !freezing(current) &&
> + !klp_kgraft_task_in_progress(current))
> clear_thread_flag(TIF_SIGPENDING);
It is not clear from this patch when TIF_SIGPENDING will be cleared.
I assume other changes add some hooks into do_notify_resume/get_signal
paths, otherwise a klp_kgraft_task_in_progress() will spin until
klp_kgraft_task_in_progress(current) becomes "false".
Oleg.
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