From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753389AbdHODAa (ORCPT ); Mon, 14 Aug 2017 23:00:30 -0400 Received: from mail-pg0-f68.google.com ([74.125.83.68]:38658 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753208AbdHODA0 (ORCPT ); Mon, 14 Aug 2017 23:00:26 -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][PATCHv5 07/13] printk: register syscore notifier Date: Tue, 15 Aug 2017 11:56:19 +0900 Message-Id: <20170815025625.1977-8-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170815025625.1977-1-sergey.senozhatsky@gmail.com> References: <20170815025625.1977-1-sergey.senozhatsky@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We need to switch to emergency printk mode in kernel_kexec(). One kernel_kexec() branch calls kernel_restart_prepare(), which updates `system_state', however, the other one, when user requested to ->preserve_context, does not and we are lacking the information in printk about kexec being executed. Register a syscore notifier so printk will be notified by syscore_suspend(). Signed-off-by: Sergey Senozhatsky --- kernel/printk/printk.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index d3f149fad85c..b14e35f94596 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -50,6 +50,7 @@ #include #include #include +#include #include #include @@ -2941,6 +2942,22 @@ static struct notifier_block printk_pm_nb = { .notifier_call = printk_pm_notify, }; +static int printk_syscore_suspend(void) +{ + printk_emergency_begin(); + return 0; +} + +static void printk_syscore_resume(void) +{ + printk_emergency_end(); +} + +static struct syscore_ops printk_syscore_ops = { + .suspend = printk_syscore_suspend, + .resume = printk_syscore_resume, +}; + static int printk_kthread_func(void *data) { while (1) { @@ -2994,6 +3011,8 @@ static int __init init_printk_kthread(void) return -EINVAL; } + register_syscore_ops(&printk_syscore_ops); + thread = kthread_run(printk_kthread_func, NULL, "printk"); if (IS_ERR(thread)) { pr_err("printk: unable to create printing thread\n"); -- 2.14.1