Messages in this thread | | | Subject | Re: [PREEMPT_RT][PATCH] printk: Enhance the condition check of msleep in pr_flush() | From | Joe Perches <> | Date | Tue, 20 Jul 2021 04:55:29 -0700 |
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On Mon, 2021-07-19 at 10:26 +0800, chao.qin@intel.com wrote: > From: Chao Qin <chao.qin@intel.com> > > There is msleep in pr_flush(). If call WARN() in the early boot > stage such as in early_initcall, pr_flush() will run into msleep > when process scheduler is not ready yet. And then the system will > sleep forever. > > Before the system_state is SYSTEM_RUNNING, make sure DO NOT sleep > in pr_flush().
Makes sense, thanks.
> diff --git 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));
trivial style note:
Logic continuations are typically at the end of the previous line. And there are few too many parentheses for my taste.
Maybe exceed 80 columns in a single line
may_sleep = preemptible() && !in_softirq() && system_state >= SYSTEM_RUNNING;
or align the continuation
may_sleep = (preemptible() && !in_softirq() && system_state >= SYSTEM_RUNNING);
or use individual lines
may_sleep = (preemptible() && !in_softirq() && system_state >= SYSTEM_RUNNING);
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