On 2021-07-30, Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote: > On 2021-07-19 17:01:51 [+0206], John Ogness wrote: >> On 2021-07-19, chao.qin@xxxxxxxxx wrote: >> > --- a/kernel/printk/printk.c >> > +++ b/kernel/printk/printk.c >> > @@ -3620,7 +3620,8 @@ bool pr_flush(int timeout_ms, bool reset_on_progress) >> > u64 diff; >> > u64 seq; >> > >> > - may_sleep = (preemptible() && !in_softirq()); >> > + may_sleep = (preemptible() && !in_softirq() >> > + && (system_state >= SYSTEM_RUNNING)); > > I don't have more context but scheduling should work starting with > SYSTEM_SCHEDULING. I also thought this, but a quick test shows that is not the case. For example, init/main.c:kernel_init() is called in preemptible context, but msleep() will hang if called at the beginning of that function. John Ogness
