From 9c2c2a049f4d7b149e8cd66418ee8f12f29ddcab Mon Sep 17 00:00:00 2001
From: Chao Qin <chao.qin@intel.com>
Date: Mon, 19 Jul 2021 10:26:50 +0800
Subject: [PATCH 016/158] printk: Enhance the condition check of msleep in
pr_flush()
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: c0b395bd0fe3("printk: add pr_flush()")
Signed-off-by: Chao Qin <chao.qin@intel.com>
Signed-off-by: Lili Li <lili.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20210719022649.3444072-1-chao.qin@intel.com
---
kernel/printk/printk.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
Index: linux-5.15.19-rt29/kernel/printk/printk.c
===================================================================
@ linux-5.15.19-rt29/kernel/printk/printk.c:3657 @ bool pr_flush(int timeout_ms, bool reset
u64 diff;
u64 seq;
- may_sleep = (preemptible() && !in_softirq());
+ may_sleep = (preemptible() &&
+ !in_softirq() &&
+ system_state >= SYSTEM_RUNNING);
seq = prb_next_seq(prb);