From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754115AbcE0N6Q (ORCPT ); Fri, 27 May 2016 09:58:16 -0400 Received: from www.linutronix.de ([62.245.132.108]:47305 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751273AbcE0N6P (ORCPT ); Fri, 27 May 2016 09:58:15 -0400 Date: Fri, 27 May 2016 15:58:12 +0200 From: Sebastian Andrzej Siewior To: linux-rt-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, Steven Rostedt Subject: [PATCH RT] kernel/printk: Don't try to print from IRQ/NMI region Message-ID: <20160527135812.GB24120@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 @@ -1502,6 +1502,11 @@ static void call_console_drivers(int lev 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) @@ -2434,6 +2439,11 @@ 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..