From patchwork Wed Jul 8 08:32:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Woody Lin X-Patchwork-Id: 11651081 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 EEDAE1709 for ; Wed, 8 Jul 2020 08:36:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D561921974 for ; Wed, 8 Jul 2020 08:36:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="vIkGHYVr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727927AbgGHIgB (ORCPT ); Wed, 8 Jul 2020 04:36:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725789AbgGHIf7 (ORCPT ); Wed, 8 Jul 2020 04:35:59 -0400 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 985F8C08C5DC for ; Wed, 8 Jul 2020 01:35:58 -0700 (PDT) Received: by mail-qv1-xf4a.google.com with SMTP id j18so28896762qvk.1 for ; Wed, 08 Jul 2020 01:35:58 -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=Yc3mqXNPbBr3iDOp2efDPDBdbhAng+8q+AaK37vlDZQ=; b=vIkGHYVrpHuqQTyUqybbBRuTBD9cUsxN3/YDagFTbXxaNP/PUt5+QqfX/QNw7X5IeR ZFdMvQCnqcguCo8azZp97dd6of/9gosFq3pgVmkPX8FRDSqZO3+4qm0ycFmbJ6LD5nLX PE1ljb7aoPMwuL/ZmsnT6c9mWW62R/MqMvpoklLp00YZGAkhqeWJOiGjEhPq4JllNrGh aegCTpduB16Saiopx26jHfJs3c3e2CJ4TOgCXAPv/8jdih2WziHBlbMqhTpiOefp8YqI RU7tUGw0vIlCO8zrycOmxZ5BlpLkbo2HE9Ih8jb/ak9bUgwMKr1P2tfT241HXEgeSCsj K3Mw== 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=Yc3mqXNPbBr3iDOp2efDPDBdbhAng+8q+AaK37vlDZQ=; b=Ly9zz5yPARMyZ7JM3Up2PpTWKyTcPIC1KwG6GSj4f4Xi7PeEunb/4jt8UcbOMiFj6C 6uREgrTogDhk04rUigHaVl6/TNsKhiz3RdUxMjnbF963JKWsN2nKqYHjRQOOnSnbM/xj n/XR3D8ml8e9JoII2aHjMDzZJGYNi3p9zCPldwgsadBUAa68JvicByGM5MurId4u5NVv bfkcYCT6LnrQJWDhiO630eApmXC0bq4kh4qHowQXsQ+OGcLwNLBnoFMbxDD59OJLGQ1u m1i8MfH3OrQYf5awJR7hKvFKvYces1oeaPzRAVaJ9LGRbmQbouorkuwL12b9ORMHSdCD 9CEQ== X-Gm-Message-State: AOAM532j7GMu48Gwu9H4UIEyi2g+wIBQ9gvCURaRplhKnw/kbLoH7HmE 3mxApKUhGg18BkeBTtbpIHc58t4Nj485JA== X-Google-Smtp-Source: ABdhPJz9BxOYrDjrxYPtk3Dyes0X4EdALlpOfgTRpFUO2s5ga8wilFqmnW/PGnqGPrWDm4u2rvU6e6QtV1/MUA== X-Received: by 2002:ad4:424a:: with SMTP id l10mr10571155qvq.29.1594197357728; Wed, 08 Jul 2020 01:35:57 -0700 (PDT) Date: Wed, 8 Jul 2020 16:32:19 +0800 Message-Id: <20200708083218.3157213-1-woodylin@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.27.0.383.g050319c2ae-goog Subject: [PATCH v4] 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 Reviewed-by: Guenter Roeck --- drivers/watchdog/softdog.c | 57 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c index 3e4885c1545e..7a1096265f18 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 +51,34 @@ 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 +87,33 @@ 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 +197,17 @@ 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; }