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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Thu, 19 May 2016 17:45:27 +0200
Subject: [PATCH 207/351] kernel/printk: Don't try to print from IRQ/NMI region
Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=4c21b40f9d1d5a3c6b0b2bb8bc0292f3ee9f8bbb
On -RT we try to acquire sleeping locks which might lead to warnings
from lockdep or a warn_on() from spin_try_lock() (which is a rtmutex on
RT).
We don't print in general from a IRQ off region so we should not try
this via console_unblank() / bust_spinlocks() as well.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/printk/printk.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index c06b1e00448d..273f2c7864b5 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1819,6 +1819,11 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
if (!console_drivers)
return;
+ if (IS_ENABLED(CONFIG_PREEMPT_RT_BASE)) {
+ if (in_irq() || in_nmi())
+ return;
+ }
+
migrate_disable();
for_each_console(con) {
if (exclusive_console && con != exclusive_console)
@@ -2595,6 +2600,11 @@ void console_unblank(void)
{
struct console *c;
+ if (IS_ENABLED(CONFIG_PREEMPT_RT_BASE)) {
+ if (in_irq() || in_nmi())
+ return;
+ }
+
/*
* console_unblank can no longer be called in interrupt context unless
* oops_in_progress is set to 1..
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