Re: [PREEMPT_RT][PATCH] printk: Enhance the condition check of msleep in pr_flush()
flat view
From: Joe Perches <joe@perches.com>
Date: 2021-07-20 11:55:51
Also in:
lkml
On Mon, 2021-07-19 at 10:26 +0800, chao.qin@intel.com wrote:
From: Chao Qin <redacted> 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.
quoted hunk ↗ jump to hunk
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
[]
quoted hunk ↗ jump to hunk
@@ -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);