From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1451C33CB6 for ; Tue, 21 Jan 2020 16:21:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A734F206A2 for ; Tue, 21 Jan 2020 16:21:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="d8/NETrS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729425AbgAUQV7 (ORCPT ); Tue, 21 Jan 2020 11:21:59 -0500 Received: from mail-wr1-f65.google.com ([209.85.221.65]:34072 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729273AbgAUQVz (ORCPT ); Tue, 21 Jan 2020 11:21:55 -0500 Received: by mail-wr1-f65.google.com with SMTP id t2so3949788wrr.1 for ; Tue, 21 Jan 2020 08:21:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=AY7gzJpVgwoLzDrLzpZZrpTzP4MowdRWmtZvJqmyD6A=; b=d8/NETrSAl8IElP67e8VdOhFfToH/47rwfj11TCQiUFupkvJw7zfh6Fr+eqJQv2WU3 OyZowoIedHdObkPaaJ/VQ6pXbAkosEJ2hSIxttQELNaDhoQegtkmSacq4P4KUpvFo+kh sX/3hxfAEMvhfvBfAh7lh8Hw0BH11E1kjDYKiTk+79ERFaf8ZTUq4lQT3wp6J+9JwWNE wKxJdmBr6wLSH5TgVhAe9tk6AduCuzVq41FTVqrRuJcGaIWMT093KDgO6RSZItx6bDuc HjAdyfgWuhYfRbMhUpAPacbh9jL8McO9mO4YiRNA/Halfn26MLR4f1EhSzjSgUSegs5X g8pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=AY7gzJpVgwoLzDrLzpZZrpTzP4MowdRWmtZvJqmyD6A=; b=BodefWPOx3bjseYQFectUWyPAZfscGHZ48YMgMIVUoC4+K6GgfyOkaZLE11V1eNguf RngN8L1ke98rmVPI6OuriXGjDdjBvBvHM0LbWzGomen9dALezw7DjiN0YYpUofHq9TJA hqy5VZxbKu5s1r9HSF5IzRZTZ+r2p54+WEnLOMUcok7nvYquUrKBLVVCydzRzlWo9osv GoI6u9hTYJtkPBsok26rd7nSeJoz+hHffIdyWxujiQUS97fXwRh6g0kaJ7i/8Lzc8g03 vJMh6Bfs/J7pKDg6L+c4983RAbJyIhiQ4q50607lkIJIFbzmWQQeuMDPuLqxuMFXz4z6 WLGw== X-Gm-Message-State: APjAAAU/FnaGUqTlLT2AnvdVOmnl9PPnil2MhkDsGjvzt2EY0h5pT26+ WxcubPXUm27XjiCcoeMCN0WgDqytlWY= X-Google-Smtp-Source: APXvYqyIxrgxURVkWUvZnOLrzwB2hVAuiqTn2hI0/2V6DyeW3ukBp0NMPEMOxAu+iw/Xe39uAXwmRA== X-Received: by 2002:adf:e683:: with SMTP id r3mr6360502wrm.38.1579623713609; Tue, 21 Jan 2020 08:21:53 -0800 (PST) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id k8sm52454388wrl.3.2020.01.21.08.21.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Jan 2020 08:21:53 -0800 (PST) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Dmitry Safonov , Guenter Roeck , Wim Van Sebroeck , linux-watchdog@vger.kernel.org Subject: [RFC 2/2] watchdog/uapi: Add WDIOS_{RUN,STOP}_ON_REBOOT Date: Tue, 21 Jan 2020 16:21:45 +0000 Message-Id: <20200121162145.166334-3-dima@arista.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200121162145.166334-1-dima@arista.com> References: <20200121162145.166334-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Many watchdog drivers use watchdog_stop_on_reboot() helper in order to stop the watchdog on system reboot. Unfortunately, this logic is coded in driver's probe function and doesn't allows user to decide what to do during shutdown/reboot. On the other side, Xen and Qemu watchdog drivers (xen_wdt and i6300esb) may be configured to either send NMI or turn off/reboot VM as the watchdog action. As the kernel may stuck at any state, sending NMIs can't reliably reboot the VM. At Arista, we benefited from the following set-up: the emulated watchdogs trigger VM reset and softdog is set to catch less severe conditions to generate vmcore. Just before reboot watchdog's timeout is increased to some good-enough value (3 mins). That keeps watchdog always running and guarantees that VM doesn't stuck. Provide new WDIOS_RUN_ON_REBOOT and WDIOS_STOP_ON_REBOOT ioctl options to set up strategy on reboot. Signed-off-by: Dmitry Safonov --- drivers/watchdog/watchdog_dev.c | 10 ++++++++++ include/linux/watchdog.h | 6 ++++++ include/uapi/linux/watchdog.h | 3 ++- 3 files changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 8766dd93028f..00135e698946 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -754,6 +754,16 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd, } if (val & WDIOS_ENABLECARD) err = watchdog_start(wdd); + + if (val & WDIOS_RUN_ON_REBOOT) { + if (val & WDIOS_STOP_ON_REBOOT) { + err = -EINVAL; + break; + } + watchdog_run_on_reboot(wdd); + } else if (val & WDIOS_STOP_ON_REBOOT) { + watchdog_stop_on_reboot(wdd); + } break; case WDIOC_KEEPALIVE: if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 417d9f37077a..9e2ca7754631 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -150,6 +150,12 @@ static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd) set_bit(WDOG_STOP_ON_REBOOT, &wdd->status); } +/* Use the following function to keep the watchdog running on reboot */ +static inline void watchdog_run_on_reboot(struct watchdog_device *wdd) +{ + clear_bit(WDOG_STOP_ON_REBOOT, &wdd->status); +} + /* Use the following function to stop the watchdog when unregistering it */ static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd) { diff --git a/include/uapi/linux/watchdog.h b/include/uapi/linux/watchdog.h index b15cde5c9054..bf19a5d3c987 100644 --- a/include/uapi/linux/watchdog.h +++ b/include/uapi/linux/watchdog.h @@ -53,6 +53,7 @@ struct watchdog_info { #define WDIOS_DISABLECARD 0x0001 /* Turn off the watchdog timer */ #define WDIOS_ENABLECARD 0x0002 /* Turn on the watchdog timer */ #define WDIOS_TEMPPANIC 0x0004 /* Kernel panic on temperature trip */ - +#define WDIOS_RUN_ON_REBOOT 0x0008 /* Keep watchdog enabled on reboot */ +#define WDIOS_STOP_ON_REBOOT 0x0010 /* Turn off the watchdog on reboot */ #endif /* _UAPI_LINUX_WATCHDOG_H */ -- 2.25.0