On 2021-07-19, chao.qin@xxxxxxxxx wrote:
> From: Chao Qin <chao.qin@xxxxxxxxx>
>
> 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().
>
> Fixes: 63cf1e4b564a ("printk: add pr_flush()")
>
> Signed-off-by: Chao Qin <chao.qin@xxxxxxxxx>
> Signed-off-by: Lili Li <lili.li@xxxxxxxxx>
Reviewed-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
> ---
> kernel/printk/printk.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 209d2392f0d8..a9b3afbdac39 100644
> --- 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));
>
> seq = prb_next_seq(prb);
>
>
> base-commit: 7e175e6b59975c8901ad370f7818937f68de45c1
> --
> 2.25.1
