From: Sebastian Andrzej Siewior Date: Thu, 19 May 2016 17:45:27 +0200 Subject: [PATCH] kernel/printk: Don't try to print from IRQ/NMI region Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.1-rt3.tar.xz 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 --- kernel/printk/printk.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1777,6 +1777,11 @@ static void call_console_drivers(const c 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) @@ -2535,6 +2540,11 @@ 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..