On Wed, Sep 15, 2021 at 04:18:01PM +0200, Vasily Gorbik wrote:
> diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
> index 291b857a6e20..2846a879f2dc 100644
> --- a/kernel/livepatch/transition.c
> +++ b/kernel/livepatch/transition.c
> @@ -278,6 +278,8 @@ static int klp_check_stack(struct task_struct *task, char *err_buf)
> * Try to safely switch a task to the target patch state. If it's currently
> * running, or it's sleeping on a to-be-patched or to-be-unpatched function, or
> * if the stack is unreliable, return false.
> + *
> + * Idle tasks are switched in the main loop when running.
> */
> static bool klp_try_switch_task(struct task_struct *task)
> {
> @@ -308,6 +310,12 @@ static bool klp_try_switch_task(struct task_struct *task)
> rq = task_rq_lock(task, &flags);
>
> if (task_running(rq, task) && task != current) {
> + /*
> + * Idle task might stay running for a long time. Switch them
> + * in the main loop.
> + */
> + if (is_idle_task(task))
> + resched_curr(rq);
> snprintf(err_buf, STACK_ERR_BUF_SIZE,
> "%s: %s:%d is running\n", __func__, task->comm,
> task->pid);
So 'recently' we grew try_invoke_on_locked_down_task() (yes, that's a
crap name), and I'm thinking this code is very similar to that. So
perhaps we re-use that.
Perhaps have func() > 0 imply resched.
I'll have a play...
