Messages in this thread | | | From | John Ogness <> | Subject | Re: [PREEMPT_RT][PATCH] printk: Enhance the condition check of msleep in pr_flush() | Date | Fri, 30 Jul 2021 16:52:42 +0206 |
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On 2021-07-30, Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote: > On 2021-07-19 17:01:51 [+0206], John Ogness wrote: >> On 2021-07-19, chao.qin@intel.com 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
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