Messages in this thread Patch in this message | | | From | John Ogness <> | Subject | RE: [PREEMPT_RT][PATCH] printk: Enhance the condition check of msleep in pr_flush() | Date | Thu, 05 Aug 2021 14:27:25 +0206 |
| |
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@intel.com> 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@intel.com> 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@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(-)
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
| |