From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 15/20] kernel/printk: Dont try to print from IRQ/NMI region Date: Tue, 12 Jul 2016 10:24:20 -0400 Message-ID: <20160712142420.030701458@goodmis.org> References: <20160712142405.634544943@goodmis.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Paul Gortmaker To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Content-Disposition: inline; filename=0015-kernel-printk-Don-t-try-to-print-from-IRQ-NMI-region.patch Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org 4.1.27-rt31-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior 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 Signed-off-by: Steven Rostedt --- kernel/printk/printk.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 899645a2ebcc..398bf2bbd3bc 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1426,6 +1426,11 @@ static void call_console_drivers(int level, const char *text, size_t 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) @@ -2392,6 +2397,11 @@ 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.. -- 2.8.1