From: Sebastian Andrzej Siewior 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 --- 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..