12 Sep
2023
12 Sep
'23
2:10 p.m.
On Mon, Sep 11, 2023 at 07:54:52PM -0400, Liam R. Howlett wrote:
Taking the mutex lock in kernel/irq/manage.c __setup_irq() is calling a cond_resched().
From what Michael said [1] in this thread, since something has already
set TIF_NEED_RESCHED, it will eventually enable interrupts on us.
I've traced this to running call_rcu() in kernel/rcu/tiny.c and is_idle_task(current) is true, which means rcu runs: /* force scheduling for rcu_qs() */ resched_cpu(0);
the task is set idle in sched_init() -> init_idle() and never changed, afaict.
Should calling init_idle() be deferred until after interrupts are all set up?