Hello Steven,
Could you please cherry-pick 83e9288d9c42("printk: Enhance the condition
check of msleep in pr_flush()") from linux-rt-devel.git (branch
linux-5.14.y-rt-rebase) for the next stable v5.10-rt release?
The commit is provided below as well.
Thanks.
John Ogness
On 2021-08-05, "Qin, Chao" <chao.qin@xxxxxxxxx> wrote:
> Do you have plan to backport this fix into v5.10.y-rt kernel?
>From 83e9288d9c4295d1195e9d780fcbc42c72ba4a83 Mon Sep 17 00:00:00 2001
From: Chao Qin <chao.qin@xxxxxxxxx>
Date: Mon, 19 Jul 2021 10:26:50 +0800
Subject: [PATCH] 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@xxxxxxxxx>
Signed-off-by: Lili Li <lili.li@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/20210719022649.3444072-1-chao.qin@xxxxxxxxx
---
kernel/printk/printk.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index e4085e2cafb5..500ae4b18864 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3661,7 +3661,9 @@ 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);
--
2.20.1
