From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751255AbdFBJEz (ORCPT ); Fri, 2 Jun 2017 05:04:55 -0400 Received: from mail-it0-f66.google.com ([209.85.214.66]:36848 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221AbdFBJEq (ORCPT ); Fri, 2 Jun 2017 05:04:46 -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][PATCHv4 3/7] printk: add enforce_emergency parameter Date: Fri, 2 Jun 2017 18:03:41 +0900 Message-Id: <20170602090345.624-4-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170602090345.624-1-sergey.senozhatsky@gmail.com> References: <20170602090345.624-1-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 45e585624ced..a1d3a69a023b 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -457,9 +457,15 @@ static DEFINE_PER_CPU(struct task_struct *, printk_kthread); 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'. -- 2.13.0