From patchwork Tue Oct 27 13:53:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 311880 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 EA078C56201 for ; Tue, 27 Oct 2020 17:51:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FCE722456 for ; Tue, 27 Oct 2020 17:51:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603821108; bh=XO1slJuy6Cd3iCL3vp7XmhG9W9rFGULZpdZ0D9mMAVg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=F37H75OURTlUTQXV3sfgMtozLYjBrMOBDNfEJgVfPW1CPuHYdK+USU0zdmWs041ut taPLJsBGUPHXPfPBi2MjzAPvaZr9B6T+N1XPwLHJTZZp+++XzN9wSMvBc4xQZk0g8Y b3PW6eHiwE28dwsomcogSSg4fU9XMlTCMuJ0X+tU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2901498AbgJ0OYA (ORCPT ); Tue, 27 Oct 2020 10:24:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:49028 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2901482AbgJ0OX4 (ORCPT ); Tue, 27 Oct 2020 10:23:56 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CF0EC20790; Tue, 27 Oct 2020 14:23:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603808635; bh=XO1slJuy6Cd3iCL3vp7XmhG9W9rFGULZpdZ0D9mMAVg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XN9atgX3jckcjFWfqZkDnXVPojv8nnnq4ZqYo69X+J+dsCE0ClVAmWfJbOLjhMWFA qmiW27o7ENV5h2za7vCEjUxVDqS3X8PQugKQY6H52NtTlP8kEhTxaEc86kztWKzxmu o5Ux8eEYqFwlrkYAbcKYMBZYIw3FCqyZYDeJgNlA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Da Xue , Sudeep Holla , Jerome Brunet , Jassi Brar , Sasha Levin Subject: [PATCH 4.19 166/264] mailbox: avoid timer start from callback Date: Tue, 27 Oct 2020 14:53:44 +0100 Message-Id: <20201027135438.485165548@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135430.632029009@linuxfoundation.org> References: <20201027135430.632029009@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jassi Brar [ Upstream commit c7dacf5b0f32957b24ef29df1207dc2cd8307743 ] If the txdone is done by polling, it is possible for msg_submit() to start the timer while txdone_hrtimer() callback is running. If the timer needs recheduling, it could already be enqueued by the time hrtimer_forward_now() is called, leading hrtimer to loudly complain. WARNING: CPU: 3 PID: 74 at kernel/time/hrtimer.c:932 hrtimer_forward+0xc4/0x110 CPU: 3 PID: 74 Comm: kworker/u8:1 Not tainted 5.9.0-rc2-00236-gd3520067d01c-dirty #5 Hardware name: Libre Computer AML-S805X-AC (DT) Workqueue: events_freezable_power_ thermal_zone_device_check pstate: 20000085 (nzCv daIf -PAN -UAO BTYPE=--) pc : hrtimer_forward+0xc4/0x110 lr : txdone_hrtimer+0xf8/0x118 [...] This can be fixed by not starting the timer from the callback path. Which requires the timer reloading as long as any message is queued on the channel, and not just when current tx is not done yet. Fixes: 0cc67945ea59 ("mailbox: switch to hrtimer for tx_complete polling") Reported-by: Da Xue Reviewed-by: Sudeep Holla Tested-by: Sudeep Holla Acked-by: Jerome Brunet Tested-by: Jerome Brunet Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin --- drivers/mailbox/mailbox.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c index 055c90b8253cb..10a559cfb7ea3 100644 --- a/drivers/mailbox/mailbox.c +++ b/drivers/mailbox/mailbox.c @@ -85,9 +85,12 @@ static void msg_submit(struct mbox_chan *chan) exit: spin_unlock_irqrestore(&chan->lock, flags); - if (!err && (chan->txdone_method & TXDONE_BY_POLL)) - /* kick start the timer immediately to avoid delays */ - hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); + /* kick start the timer immediately to avoid delays */ + if (!err && (chan->txdone_method & TXDONE_BY_POLL)) { + /* but only if not already active */ + if (!hrtimer_active(&chan->mbox->poll_hrt)) + hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); + } } static void tx_tick(struct mbox_chan *chan, int r) @@ -125,11 +128,10 @@ static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer) struct mbox_chan *chan = &mbox->chans[i]; if (chan->active_req && chan->cl) { + resched = true; txdone = chan->mbox->ops->last_tx_done(chan); if (txdone) tx_tick(chan, 0); - else - resched = true; } }