From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752484AbdEIIaL (ORCPT ); Tue, 9 May 2017 04:30:11 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:33337 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751703AbdEIIaJ (ORCPT ); Tue, 9 May 2017 04:30:09 -0400 From: Sergey Senozhatsky To: Petr Mladek , Steven Rostedt Cc: Jan Kara , Andrew Morton , Peter Zijlstra , "Rafael J . Wysocki" , Eric Biederman , Greg Kroah-Hartman , Jiri Slaby , Pavel Machek , Andreas Mohr , Tetsuo Handa , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [RFC][PATCHv3 3/5] printk: add enforce_emergency parameter Date: Tue, 9 May 2017 17:28:57 +0900 Message-Id: <20170509082859.854-4-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170509082859.854-1-sergey.senozhatsky@gmail.com> References: <20170509082859.854-1-sergey.senozhatsky@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This param permits user-space to forcibly on/off printk emergency mode via /sys/module/printk/parameters/enforce_emergency node. Signed-off-by: Sergey Senozhatsky --- kernel/printk/printk.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index a113f684066c..ba640fbcee7c 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -455,9 +455,15 @@ static struct task_struct *printk_kthread __read_mostly; static atomic_t printk_emergency __read_mostly; /* * Disable printk_kthread permanently. Unlike `oops_in_progress' - * it doesn't go back to 0. + * it doesn't go back to 0 (unless set by user-space). */ static bool printk_enforce_emergency __read_mostly; + +module_param_named(enforce_emergency, printk_enforce_emergency, + bool, 0644); +MODULE_PARM_DESC(printk_enforce_emergency, + "don't offload message printing to printk kthread"); + /* * The number of lines a task can print before offloading printing * job to printk_kthread. 0 indicates 'no limit'. -- 2.12.2