From patchwork Mon Dec 28 12:49:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 352748 Delivered-To: patch@linaro.org Received: by 2002:a02:85a7:0:0:0:0:0 with SMTP id d36csp9865525jai; Mon, 28 Dec 2020 08:20:16 -0800 (PST) X-Google-Smtp-Source: ABdhPJy7lMDjfRd7YQwfpskAQdHWka1eqRe+7NKhESb3c81ALs98u+w7nTX+Lut91h6+rZyVeqER X-Received: by 2002:a17:906:7d98:: with SMTP id v24mr42307046ejo.129.1609172416051; Mon, 28 Dec 2020 08:20:16 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1609172416; cv=none; d=google.com; s=arc-20160816; b=hrlUeF0D1HhWV9C5Gw7mwX7GM7xVNDTh6+Xtl8oXvZLJgYmtX64Q0IGxWGYTgoK+DL BlR4K5B6rWriEgqsHeaPjpbSvjRXZ6tWXbA0KhHXKS+nI2GjCRna3ZpevbpeWzlkCELE QE1KQZDbUO3or1BpHnfV25/KixqyBPvuC2fpquOr7tAj3AM9Qu1TDt7r73fn50knX7PW SJCDsvofBdyN95ssaCviIioetLrVIWjA8ODcueJvKY4johYyikrFcKZ+l/CTof/x+a+Q mx2IFuWTdwt06KSJ3VS3ieFzNIba/W779gk2ywH9QTgkWJLFjJ8u+UycSsyepanif0kV C2kA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=8leudDzkmP9dygQ2J+kYpDuJy6sWUqkxO7gbz8h4kOw=; b=edANBDx3OKAwJ91QCW02DaQ7cNGWtCEE2N8YGiBFhtk1D0dFkATw9JzOJJSRKLhvny RVAFwP2nJiZUqDuEqWTRALkVRcSB3B/sgUTeFV0XO2ow8LVHBFdD5r/G3Sy5e7fQngEb TWF4IiHIq9hmnjmWkq7zqb/c3iBKNAYS5srBDYF9O0cg5bcMPoompTCesxSovThnS6cg Or1XmoVPKh9Y+O3059N9GDzkEf/OXFE2wdqjBSygrc6ejMFjc5QkMdNQtg4JfpNYPPht GDBCilifDZ94XayT9OjRcQwoGjwQO8lphAtzXjbCyBHxKPS/wVyPo9a2jbvYGIdLtyKH M5wA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=AzeZwIFM; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id d12si19406563edh.221.2020.12.28.08.20.15; Mon, 28 Dec 2020 08:20:16 -0800 (PST) Received-SPF: pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=AzeZwIFM; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732738AbgL1NPo (ORCPT + 14 others); Mon, 28 Dec 2020 08:15:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:44004 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732732AbgL1NPo (ORCPT ); Mon, 28 Dec 2020 08:15:44 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7C1C122AAD; Mon, 28 Dec 2020 13:15:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609161303; bh=QSGODTnlgU389f9orKrL1mY5vD+RHSlY6cCUFj3NOCM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AzeZwIFMLGQmQa08hl5QZ/znKCokbsrDmiglUUTI5+QwQ0hD1ME6e3bxvhomyiNk4 03T5n0wQwqglbXqPgKJANkS35yRlloh4xqBs6R1w4eKKT4QnEqeX59sZ2YscNWAoSO keNABI2LruPZME34ZL/gqxETgSrrfdzpQgpp8yDg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Manivannan Sadhasivam , Guenter Roeck , Wim Van Sebroeck , Sasha Levin Subject: [PATCH 4.14 168/242] watchdog: qcom: Avoid context switch in restart handler Date: Mon, 28 Dec 2020 13:49:33 +0100 Message-Id: <20201228124912.968716627@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124904.654293249@linuxfoundation.org> References: <20201228124904.654293249@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Manivannan Sadhasivam [ Upstream commit 7948fab26bcc468aa2a76462f441291b5fb0d5c7 ] The use of msleep() in the restart handler will cause scheduler to induce a context switch which is not desirable. This generates below warning on SDX55 when WDT is the only available restart source: [ 39.800188] reboot: Restarting system [ 39.804115] ------------[ cut here ]------------ [ 39.807855] WARNING: CPU: 0 PID: 678 at kernel/rcu/tree_plugin.h:297 rcu_note_context_switch+0x190/0x764 [ 39.812538] Modules linked in: [ 39.821954] CPU: 0 PID: 678 Comm: reboot Not tainted 5.10.0-rc1-00063-g33a9990d1d66-dirty #47 [ 39.824854] Hardware name: Generic DT based system [ 39.833470] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [ 39.838154] [] (show_stack) from [] (dump_stack+0x8c/0xa0) [ 39.846049] [] (dump_stack) from [] (__warn+0xd8/0xf0) [ 39.853058] [] (__warn) from [] (warn_slowpath_fmt+0x64/0xc8) [ 39.859925] [] (warn_slowpath_fmt) from [] (rcu_note_context_switch+0x190/0x764) [ 39.867503] [] (rcu_note_context_switch) from [] (__schedule+0x84/0x640) [ 39.876685] [] (__schedule) from [] (schedule+0x58/0x10c) [ 39.885095] [] (schedule) from [] (schedule_timeout+0x1e8/0x3d4) [ 39.892135] [] (schedule_timeout) from [] (msleep+0x2c/0x38) [ 39.899947] [] (msleep) from [] (qcom_wdt_restart+0xc4/0xcc) [ 39.907319] [] (qcom_wdt_restart) from [] (watchdog_restart_notifier+0x18/0x28) [ 39.914715] [] (watchdog_restart_notifier) from [] (atomic_notifier_call_chain+0x60/0x84) [ 39.923487] [] (atomic_notifier_call_chain) from [] (machine_restart+0x78/0x7c) [ 39.933551] [] (machine_restart) from [] (__do_sys_reboot+0xdc/0x1e0) [ 39.942397] [] (__do_sys_reboot) from [] (ret_fast_syscall+0x0/0x54) [ 39.950721] Exception stack(0xc3e0bfa8 to 0xc3e0bff0) [ 39.958855] bfa0: 0001221c bed2fe24 fee1dead 28121969 01234567 00000000 [ 39.963832] bfc0: 0001221c bed2fe24 00000003 00000058 000225e0 00000000 00000000 00000000 [ 39.971985] bfe0: b6e62560 bed2fc84 00010fd8 b6e62580 [ 39.980124] ---[ end trace 3f578288bad866e4 ]--- Hence, replace msleep() with mdelay() to fix this issue. Fixes: 05e487d905ab ("watchdog: qcom: register a restart notifier") Signed-off-by: Manivannan Sadhasivam Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/20201207060005.21293-1-manivannan.sadhasivam@linaro.org Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck Signed-off-by: Sasha Levin --- drivers/watchdog/qcom-wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.27.0 diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c index 780971318810d..1a0005a8fadb2 100644 --- a/drivers/watchdog/qcom-wdt.c +++ b/drivers/watchdog/qcom-wdt.c @@ -121,7 +121,7 @@ static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action, */ wmb(); - msleep(150); + mdelay(150); return 0; }