From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754384AbdLDNte (ORCPT ); Mon, 4 Dec 2017 08:49:34 -0500 Received: from mail-pf0-f193.google.com ([209.85.192.193]:45748 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753594AbdLDNt2 (ORCPT ); Mon, 4 Dec 2017 08:49:28 -0500 X-Google-Smtp-Source: AGs4zMb4r8G7dmMzIPKprz6MzUNuELNE7Bn1SgMigtVYpbAzVkMMsBCIsA1PygXZnr37vJyYSs97Ng== From: Sergey Senozhatsky To: Steven Rostedt , Petr Mladek Cc: Jan Kara , Andrew Morton , Peter Zijlstra , Rafael Wysocki , Pavel Machek , Tetsuo Handa , Tejun Heo , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [RFC][PATCHv6 07/12] printk: register syscore notifier Date: Mon, 4 Dec 2017 22:48:20 +0900 Message-Id: <20171204134825.7822-8-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171204134825.7822-1-sergey.senozhatsky@gmail.com> References: <20171204134825.7822-1-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 a427cee2aa00..372c71f69e8e 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -49,6 +49,7 @@ #include #include #include +#include #include #include @@ -2914,6 +2915,22 @@ static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { .flags = IRQ_WORK_LAZY, }; +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) { @@ -2961,6 +2978,8 @@ static int __init init_printk_kthread(void) if (!alloc_cpumask_var(&printk_offload_cpus, GFP_KERNEL)) return -ENOMEM; + 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"); -- 2.15.1