From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 4/8] kernel/printk: Dont try to print from IRQ/NMI region Date: Tue, 12 Jul 2016 12:57:53 -0400 Message-ID: <20160712165802.448524477@goodmis.org> References: <20160712165749.741663758@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=0004-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 3.10.102-rt113-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.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/kernel/printk.c b/kernel/printk.c index 1b7fbc73c125..55b6871f21e2 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -1302,6 +1302,11 @@ 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) @@ -2236,6 +2241,11 @@ 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