From patchwork Wed Jul 1 11:03:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Woody Lin X-Patchwork-Id: 11636139 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 86AF092A for ; Wed, 1 Jul 2020 11:04:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BC8D20702 for ; Wed, 1 Jul 2020 11:04:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="GXhjl7JP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730266AbgGALEa (ORCPT ); Wed, 1 Jul 2020 07:04:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730202AbgGALE3 (ORCPT ); Wed, 1 Jul 2020 07:04:29 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D818FC061755 for ; Wed, 1 Jul 2020 04:04:28 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id j3so26147558yba.14 for ; Wed, 01 Jul 2020 04:04:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=t8UIv8OCBdFSlfH8WcuPC7BgMOwuSg0GOer8MWGdwI4=; b=GXhjl7JPotLn0ZyLk0+tSraoJOuXZajMMPTu6L26AbxxcyqvK4+OMkqjAGWhmOrDFi R7ahpl+B1kU+Jt6+rnVQDEE8LvnyHWCffDCtkpOYd5VdFQzfGsoJh5Y6oCvsmHyQbHp5 MiVsqtvV6f6mU9N360Gsovy0xwWEEo/STi1Z3ATvp6Mu70vMUvBqPR3M1esowxXZdCYk 6OAu4EbOE1RV4mFlaYx+g6dyGN6LHMe+Qc9PhRE9+PpV5quvfF6ra+o55hlBCNwsA/0y 23Mes8j42BWoc3ajOyhIqZfCQH63BOIl9HDTGaRxLuy/amZmRdS2Dpn5Ism5D3HcwdKd V/UQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=t8UIv8OCBdFSlfH8WcuPC7BgMOwuSg0GOer8MWGdwI4=; b=E0KcEntMRJe0eU5vyo/yi9FQ0gh0jeLLybXDxh838yMI/ss1xVNGWyrGb7TJ6viXjw CRyQIg4lC+455fQcmR7xrU+n6WvcnOEE/pc5BZgRmIYs7Fl8y0CMd8u3G0NU9sdCteZ1 M5l5i7DH5Gwawzb9mqp1B3QnTdOGHaRof4eII3u0MkQrf8DjqYpmsPTzGHj4hXFc/4D3 cRyqDSpT0oN8mw2d+Q+5srEc2uXqd+uqe4JgQcrmLw7/2jwQ07FSObSbVRrzs2WdI4XU dM2JNN5t3GgzupeXmCD4bq2n8kTG3LqM+u204bfQSD/chX37Lumy5E2kYvim3mahmVid TfQQ== X-Gm-Message-State: AOAM530M0XvqzLPqtZe1PyzIZkIN0eVwxfZDpTybAfC2pJjbFuOa2ch4 u18eMgfmdg+OCYppZcQzC6Au0/hJQ1fTyg== X-Google-Smtp-Source: ABdhPJypmVDPxtS/LjlwoJEFxLSnlJ3LmBNDgsfH3leKes7N0MS6dbZGi/yTIWfYZxUu/itRtrpNEFaIV1J3TA== X-Received: by 2002:a25:be02:: with SMTP id h2mr41751730ybk.315.1593601467846; Wed, 01 Jul 2020 04:04:27 -0700 (PDT) Date: Wed, 1 Jul 2020 19:03:40 +0800 Message-Id: <20200701110339.2833449-1-woodylin@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.27.0.212.ge8ba1cc988-goog Subject: [PATCH v3] softdog: Add options 'soft_reboot_cmd' and 'soft_active_on_boot' From: Woody Lin To: Wim Van Sebroeck , Guenter Roeck Cc: linux-watchdog@vger.kernel.org, Woody Lin Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Add module parameters 'soft_reboot_cmd' and 'soft_active_on_boot' for customizing softdog configuration; config reboot command by assigning soft_reboot_cmd, and set soft_active_on_boot to start up softdog timer at module initialization stage. Signed-off-by: Woody Lin --- drivers/watchdog/softdog.c | 56 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c index 3e4885c1545e..8c8d214b6aa7 100644 --- a/drivers/watchdog/softdog.c +++ b/drivers/watchdog/softdog.c @@ -20,11 +20,13 @@ #include #include #include +#include #include #include #include #include #include +#include #define TIMER_MARGIN 60 /* Default is 60 seconds */ static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */ @@ -49,11 +51,33 @@ module_param(soft_panic, int, 0); MODULE_PARM_DESC(soft_panic, "Softdog action, set to 1 to panic, 0 to reboot (default=0)"); +static char *soft_reboot_cmd; +module_param(soft_reboot_cmd, charp, 0000); +MODULE_PARM_DESC(soft_reboot_cmd, + "Set reboot command. Emergency reboot takes place if unset"); + +static bool soft_active_on_boot; +module_param(soft_active_on_boot, bool, 0000); +MODULE_PARM_DESC(soft_active_on_boot, + "Set to true to active Softdog on boot (default=false)"); + static struct hrtimer softdog_ticktock; static struct hrtimer softdog_preticktock; +static int reboot_kthread_fn(void *data) +{ + kernel_restart(soft_reboot_cmd); + return -EPERM; /* Should not reach here */ +} + +static void reboot_work_fn(struct work_struct *unused) +{ + kthread_run(reboot_kthread_fn, NULL, "softdog_reboot"); +} + static enum hrtimer_restart softdog_fire(struct hrtimer *timer) { + static bool soft_reboot_fired; module_put(THIS_MODULE); if (soft_noboot) { pr_crit("Triggered - Reboot ignored\n"); @@ -62,6 +86,33 @@ static enum hrtimer_restart softdog_fire(struct hrtimer *timer) panic("Software Watchdog Timer expired"); } else { pr_crit("Initiating system reboot\n"); + if (!soft_reboot_fired && soft_reboot_cmd != NULL) { + static DECLARE_WORK(reboot_work, reboot_work_fn); + /* + * The 'kernel_restart' is a 'might-sleep' operation. + * Also, executing it in system-wide workqueues blocks + * any driver from using the same workqueue in its + * shutdown callback function. Thus, we should execute + * the 'kernel_restart' in a standalone kernel thread. + * But since starting a kernel thread is also a + * 'might-sleep' operation, so the 'reboot_work' is + * required as a launcher of the kernel thread. + * + * After request the reboot, restart the timer to + * schedule an 'emergency_restart' reboot after + * 'TIMER_MARGIN' seconds. It's because if the softdog + * hangs, it might be because of scheduling issues. And + * if that is the case, both 'schedule_work' and + * 'kernel_restart' may possibly be malfunctional at the + * same time. + */ + soft_reboot_fired = true; + schedule_work(&reboot_work); + hrtimer_add_expires_ns(timer, + (u64)TIMER_MARGIN * NSEC_PER_SEC); + + return HRTIMER_RESTART; + } emergency_restart(); pr_crit("Reboot didn't ?????\n"); } @@ -145,12 +196,17 @@ static int __init softdog_init(void) softdog_preticktock.function = softdog_pretimeout; } + if (soft_active_on_boot) + softdog_ping(&softdog_dev); + ret = watchdog_register_device(&softdog_dev); if (ret) return ret; pr_info("initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n", soft_noboot, softdog_dev.timeout, soft_panic, nowayout); + pr_info(" soft_reboot_cmd=%s soft_active_on_boot=%d\n", + soft_reboot_cmd, soft_active_on_boot); return 0; }