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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1907AC433EF for ; Fri, 25 Feb 2022 15:20:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241522AbiBYPUy (ORCPT ); Fri, 25 Feb 2022 10:20:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233524AbiBYPUv (ORCPT ); Fri, 25 Feb 2022 10:20:51 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5EEC8C7DF; Fri, 25 Feb 2022 07:20:17 -0800 (PST) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 20E541F380; Fri, 25 Feb 2022 15:20:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1645802416; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=76D+b8ZUFKHayJqezaXTrIOKH/+w6Mr9BDaG1qJPaqM=; b=uiwU9753hHXtDfEByGOp/4k3/mpSpC2iPS5R74LN2olK1KIV4kIuD6y8ARyLKPI+57XebW laXnAzMwXNXHJgSFsi5gA5ifwF1cCKT2ypgNk9DHv/UzKegXnyQUGwO9FQLe7NALffYOqs LFAeojvzfBLhLsnUVHoCuDy01kc+AaU= Received: from suse.cz (unknown [10.100.216.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 81174A3B83; Fri, 25 Feb 2022 15:20:15 +0000 (UTC) Date: Fri, 25 Feb 2022 16:20:15 +0100 From: Petr Mladek To: Lecopzer Chen Cc: linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Mark Rutland , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , davem@davemloft.net, Matthias Brugger , Marc Zyngier , Julien Thierry , Kees Cook , Masahiro Yamada , Andrew Morton , Wang Qing , Luis Chamberlain , Xiaoming Ni , linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, sparclinux@vger.kernel.org, linux-mediatek@lists.infradead.org, sumit.garg@linaro.org, kernelfans@gmail.com, yj.chiang@mediatek.com Subject: Re: [PATCH 4/5] kernel/watchdog: Adapt the watchdog_hld interface for async model Message-ID: References: <20220212104349.14266-1-lecopzer.chen@mediatek.com> <20220212104349.14266-5-lecopzer.chen@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220212104349.14266-5-lecopzer.chen@mediatek.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat 2022-02-12 18:43:48, Lecopzer Chen wrote: > From: Pingfan Liu > > from: Pingfan Liu > > When lockup_detector_init()->watchdog_nmi_probe(), PMU may be not ready > yet. E.g. on arm64, PMU is not ready until > device_initcall(armv8_pmu_driver_init). And it is deeply integrated > with the driver model and cpuhp. Hence it is hard to push this > initialization before smp_init(). > > But it is easy to take an opposite approach by enabling watchdog_hld to > get the capability of PMU async. > > The async model is achieved by expanding watchdog_nmi_probe() with > -EBUSY, and a re-initializing work_struct which waits on a wait_queue_head. > > Signed-off-by: Pingfan Liu > Co-developed-by: Lecopzer Chen > Signed-off-by: Lecopzer Chen > --- > kernel/watchdog.c | 56 +++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 54 insertions(+), 2 deletions(-) > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index b71d434cf648..fa8490cfeef8 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -839,16 +843,64 @@ static void __init watchdog_sysctl_init(void) > #define watchdog_sysctl_init() do { } while (0) > #endif /* CONFIG_SYSCTL */ > > +static void lockup_detector_delay_init(struct work_struct *work); > +enum hld_detector_state detector_delay_init_state __initdata; I would call this "lockup_detector_init_state" to use the same naming scheme everywhere. > + > +struct wait_queue_head hld_detector_wait __initdata = > + __WAIT_QUEUE_HEAD_INITIALIZER(hld_detector_wait); > + > +static struct work_struct detector_work __initdata = I would call this "lockup_detector_work" to use the same naming scheme everywhere. > + __WORK_INITIALIZER(detector_work, lockup_detector_delay_init); > + > +static void __init lockup_detector_delay_init(struct work_struct *work) > +{ > + int ret; > + > + wait_event(hld_detector_wait, > + detector_delay_init_state == DELAY_INIT_READY); DELAY_INIT_READY is defined in the 5th patch. There are many other build errors because this patch uses something that is defined in the 5th patch. > + ret = watchdog_nmi_probe(); > + if (!ret) { > + nmi_watchdog_available = true; > + lockup_detector_setup(); > + } else { > + WARN_ON(ret == -EBUSY); Why WARN_ON(), please? Note that it might cause panic() when "panic_on_warn" command line parameter is used. Also the backtrace will not help much. The context is well known. This code is called from a workqueue worker. > + pr_info("Perf NMI watchdog permanently disabled\n"); > + } > +} > + > +/* Ensure the check is called after the initialization of PMU driver */ > +static int __init lockup_detector_check(void) > +{ > + if (detector_delay_init_state < DELAY_INIT_WAIT) > + return 0; > + > + if (WARN_ON(detector_delay_init_state == DELAY_INIT_WAIT)) { Again. Is WARN_ON() needed? Also the condition looks wrong. IMHO, this is the expected state. > + detector_delay_init_state = DELAY_INIT_READY; > + wake_up(&hld_detector_wait); > + } > + flush_work(&detector_work); > + return 0; > +} > +late_initcall_sync(lockup_detector_check); Otherwise, it make sense. Best Regards, Petr PS: I am not going to review the last patch because I am no familiar with arm. I reviewed just the changes in the generic watchdog code. 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 437CBC433F5 for ; Fri, 25 Feb 2022 15:20:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=H3gf3tRshkjbg+BWv294ig0zTo4Vcgz1sSVkqsaRZeA=; b=ZlrgKCAx0kYdUA 0/Pelg5176C9BH1TcQBTWkdZF7HBR2A5ZX5y0k8K3vAXhq5bpc5ST2fYr5ZrkafLq4eRATVqcjkpK BRcMewze8+lty3wNoNa9Uk3G2ZTi7q61ZtXNiMkVIC5R38Js3uxejEwORzH5D7pZFUwWQTapj1JwD suLqwGQsomIeDRzYazbwTiSPFb8cxcXBc1oMlMgwg6p+QrfjUgE3+N2o6E5qIJ6ENc5dl5MzyBgls Zipe8+B3AwBKhvrV4vqDPPoKCARCwVbAjWc4sob3+MqmOchrloGy8wvabfHtWD13rdkhvbsIUXs6H 8hBCU/eOa/t1/2NRCryQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nNcOX-005a3Q-DY; Fri, 25 Feb 2022 15:20:33 +0000 Received: from smtp-out2.suse.de ([195.135.220.29]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nNcOK-005ZzE-NU; Fri, 25 Feb 2022 15:20:22 +0000 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 20E541F380; Fri, 25 Feb 2022 15:20:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1645802416; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=76D+b8ZUFKHayJqezaXTrIOKH/+w6Mr9BDaG1qJPaqM=; b=uiwU9753hHXtDfEByGOp/4k3/mpSpC2iPS5R74LN2olK1KIV4kIuD6y8ARyLKPI+57XebW laXnAzMwXNXHJgSFsi5gA5ifwF1cCKT2ypgNk9DHv/UzKegXnyQUGwO9FQLe7NALffYOqs LFAeojvzfBLhLsnUVHoCuDy01kc+AaU= Received: from suse.cz (unknown [10.100.216.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 81174A3B83; Fri, 25 Feb 2022 15:20:15 +0000 (UTC) Date: Fri, 25 Feb 2022 16:20:15 +0100 From: Petr Mladek To: Lecopzer Chen Cc: linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Mark Rutland , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , davem@davemloft.net, Matthias Brugger , Marc Zyngier , Julien Thierry , Kees Cook , Masahiro Yamada , Andrew Morton , Wang Qing , Luis Chamberlain , Xiaoming Ni , linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, sparclinux@vger.kernel.org, linux-mediatek@lists.infradead.org, sumit.garg@linaro.org, kernelfans@gmail.com, yj.chiang@mediatek.com Subject: Re: [PATCH 4/5] kernel/watchdog: Adapt the watchdog_hld interface for async model Message-ID: References: <20220212104349.14266-1-lecopzer.chen@mediatek.com> <20220212104349.14266-5-lecopzer.chen@mediatek.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220212104349.14266-5-lecopzer.chen@mediatek.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220225_072020_969614_7514086C X-CRM114-Status: GOOD ( 32.49 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Sat 2022-02-12 18:43:48, Lecopzer Chen wrote: > From: Pingfan Liu > > from: Pingfan Liu > > When lockup_detector_init()->watchdog_nmi_probe(), PMU may be not ready > yet. E.g. on arm64, PMU is not ready until > device_initcall(armv8_pmu_driver_init). And it is deeply integrated > with the driver model and cpuhp. Hence it is hard to push this > initialization before smp_init(). > > But it is easy to take an opposite approach by enabling watchdog_hld to > get the capability of PMU async. > > The async model is achieved by expanding watchdog_nmi_probe() with > -EBUSY, and a re-initializing work_struct which waits on a wait_queue_head. > > Signed-off-by: Pingfan Liu > Co-developed-by: Lecopzer Chen > Signed-off-by: Lecopzer Chen > --- > kernel/watchdog.c | 56 +++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 54 insertions(+), 2 deletions(-) > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index b71d434cf648..fa8490cfeef8 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -839,16 +843,64 @@ static void __init watchdog_sysctl_init(void) > #define watchdog_sysctl_init() do { } while (0) > #endif /* CONFIG_SYSCTL */ > > +static void lockup_detector_delay_init(struct work_struct *work); > +enum hld_detector_state detector_delay_init_state __initdata; I would call this "lockup_detector_init_state" to use the same naming scheme everywhere. > + > +struct wait_queue_head hld_detector_wait __initdata = > + __WAIT_QUEUE_HEAD_INITIALIZER(hld_detector_wait); > + > +static struct work_struct detector_work __initdata = I would call this "lockup_detector_work" to use the same naming scheme everywhere. > + __WORK_INITIALIZER(detector_work, lockup_detector_delay_init); > + > +static void __init lockup_detector_delay_init(struct work_struct *work) > +{ > + int ret; > + > + wait_event(hld_detector_wait, > + detector_delay_init_state == DELAY_INIT_READY); DELAY_INIT_READY is defined in the 5th patch. There are many other build errors because this patch uses something that is defined in the 5th patch. > + ret = watchdog_nmi_probe(); > + if (!ret) { > + nmi_watchdog_available = true; > + lockup_detector_setup(); > + } else { > + WARN_ON(ret == -EBUSY); Why WARN_ON(), please? Note that it might cause panic() when "panic_on_warn" command line parameter is used. Also the backtrace will not help much. The context is well known. This code is called from a workqueue worker. > + pr_info("Perf NMI watchdog permanently disabled\n"); > + } > +} > + > +/* Ensure the check is called after the initialization of PMU driver */ > +static int __init lockup_detector_check(void) > +{ > + if (detector_delay_init_state < DELAY_INIT_WAIT) > + return 0; > + > + if (WARN_ON(detector_delay_init_state == DELAY_INIT_WAIT)) { Again. Is WARN_ON() needed? Also the condition looks wrong. IMHO, this is the expected state. > + detector_delay_init_state = DELAY_INIT_READY; > + wake_up(&hld_detector_wait); > + } > + flush_work(&detector_work); > + return 0; > +} > +late_initcall_sync(lockup_detector_check); Otherwise, it make sense. Best Regards, Petr PS: I am not going to review the last patch because I am no familiar with arm. I reviewed just the changes in the generic watchdog code. _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 918C9C433F5 for ; Fri, 25 Feb 2022 15:21:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=uz+2T9uWpdGS+krblISndABRfvqns8MGgGxAzSbvNNE=; b=nA9m8PWHUFBZbY ZGa+Al0+Kh0vEPq0/qWYQm1Z5+KK7vB9zpJN10TgrUaajljijybldP4xWg/PHyIrUsef0uPOnMI/U DUBOx+pZnuFyVyz7IYjbCYJomna+Hxf5YqQ/s1OrjG+Vn7/bKMg64/pyBihe9wlO772O053yP/0wt ZQ9eVEw/8wCHIXelmX9iTduVwMcjMXE64nGWybc2HsyQDbDr+7sq7Mq8kJ7WDfWUiQEwkA7/q9ypk E3/ClOrlFt5qaDgREz9tU/VWrHmHEx26AjJ/t5u4JUS2ooay5EV53cen7Ak7i4HOudCp3YuwYGUrm NXrXl/ndgCBlW7LAhfEA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nNcOO-005a1B-AA; Fri, 25 Feb 2022 15:20:24 +0000 Received: from smtp-out2.suse.de ([195.135.220.29]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nNcOK-005ZzE-NU; Fri, 25 Feb 2022 15:20:22 +0000 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 20E541F380; Fri, 25 Feb 2022 15:20:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1645802416; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=76D+b8ZUFKHayJqezaXTrIOKH/+w6Mr9BDaG1qJPaqM=; b=uiwU9753hHXtDfEByGOp/4k3/mpSpC2iPS5R74LN2olK1KIV4kIuD6y8ARyLKPI+57XebW laXnAzMwXNXHJgSFsi5gA5ifwF1cCKT2ypgNk9DHv/UzKegXnyQUGwO9FQLe7NALffYOqs LFAeojvzfBLhLsnUVHoCuDy01kc+AaU= Received: from suse.cz (unknown [10.100.216.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 81174A3B83; Fri, 25 Feb 2022 15:20:15 +0000 (UTC) Date: Fri, 25 Feb 2022 16:20:15 +0100 From: Petr Mladek To: Lecopzer Chen Cc: linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Mark Rutland , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , davem@davemloft.net, Matthias Brugger , Marc Zyngier , Julien Thierry , Kees Cook , Masahiro Yamada , Andrew Morton , Wang Qing , Luis Chamberlain , Xiaoming Ni , linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, sparclinux@vger.kernel.org, linux-mediatek@lists.infradead.org, sumit.garg@linaro.org, kernelfans@gmail.com, yj.chiang@mediatek.com Subject: Re: [PATCH 4/5] kernel/watchdog: Adapt the watchdog_hld interface for async model Message-ID: References: <20220212104349.14266-1-lecopzer.chen@mediatek.com> <20220212104349.14266-5-lecopzer.chen@mediatek.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220212104349.14266-5-lecopzer.chen@mediatek.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220225_072020_969614_7514086C X-CRM114-Status: GOOD ( 32.49 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat 2022-02-12 18:43:48, Lecopzer Chen wrote: > From: Pingfan Liu > > from: Pingfan Liu > > When lockup_detector_init()->watchdog_nmi_probe(), PMU may be not ready > yet. E.g. on arm64, PMU is not ready until > device_initcall(armv8_pmu_driver_init). And it is deeply integrated > with the driver model and cpuhp. Hence it is hard to push this > initialization before smp_init(). > > But it is easy to take an opposite approach by enabling watchdog_hld to > get the capability of PMU async. > > The async model is achieved by expanding watchdog_nmi_probe() with > -EBUSY, and a re-initializing work_struct which waits on a wait_queue_head. > > Signed-off-by: Pingfan Liu > Co-developed-by: Lecopzer Chen > Signed-off-by: Lecopzer Chen > --- > kernel/watchdog.c | 56 +++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 54 insertions(+), 2 deletions(-) > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index b71d434cf648..fa8490cfeef8 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -839,16 +843,64 @@ static void __init watchdog_sysctl_init(void) > #define watchdog_sysctl_init() do { } while (0) > #endif /* CONFIG_SYSCTL */ > > +static void lockup_detector_delay_init(struct work_struct *work); > +enum hld_detector_state detector_delay_init_state __initdata; I would call this "lockup_detector_init_state" to use the same naming scheme everywhere. > + > +struct wait_queue_head hld_detector_wait __initdata = > + __WAIT_QUEUE_HEAD_INITIALIZER(hld_detector_wait); > + > +static struct work_struct detector_work __initdata = I would call this "lockup_detector_work" to use the same naming scheme everywhere. > + __WORK_INITIALIZER(detector_work, lockup_detector_delay_init); > + > +static void __init lockup_detector_delay_init(struct work_struct *work) > +{ > + int ret; > + > + wait_event(hld_detector_wait, > + detector_delay_init_state == DELAY_INIT_READY); DELAY_INIT_READY is defined in the 5th patch. There are many other build errors because this patch uses something that is defined in the 5th patch. > + ret = watchdog_nmi_probe(); > + if (!ret) { > + nmi_watchdog_available = true; > + lockup_detector_setup(); > + } else { > + WARN_ON(ret == -EBUSY); Why WARN_ON(), please? Note that it might cause panic() when "panic_on_warn" command line parameter is used. Also the backtrace will not help much. The context is well known. This code is called from a workqueue worker. > + pr_info("Perf NMI watchdog permanently disabled\n"); > + } > +} > + > +/* Ensure the check is called after the initialization of PMU driver */ > +static int __init lockup_detector_check(void) > +{ > + if (detector_delay_init_state < DELAY_INIT_WAIT) > + return 0; > + > + if (WARN_ON(detector_delay_init_state == DELAY_INIT_WAIT)) { Again. Is WARN_ON() needed? Also the condition looks wrong. IMHO, this is the expected state. > + detector_delay_init_state = DELAY_INIT_READY; > + wake_up(&hld_detector_wait); > + } > + flush_work(&detector_work); > + return 0; > +} > +late_initcall_sync(lockup_detector_check); Otherwise, it make sense. Best Regards, Petr PS: I am not going to review the last patch because I am no familiar with arm. I reviewed just the changes in the generic watchdog code. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel