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=-9.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 59B4CC433DF for ; Fri, 16 Oct 2020 09:02:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D5B6420872 for ; Fri, 16 Oct 2020 09:02:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=baylibre-com.20150623.gappssmtp.com header.i=@baylibre-com.20150623.gappssmtp.com header.b="RJw96zwU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394885AbgJPJCK (ORCPT ); Fri, 16 Oct 2020 05:02:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394536AbgJPJCH (ORCPT ); Fri, 16 Oct 2020 05:02:07 -0400 Received: from mail-ed1-x542.google.com (mail-ed1-x542.google.com [IPv6:2a00:1450:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 899ECC061755 for ; Fri, 16 Oct 2020 02:02:05 -0700 (PDT) Received: by mail-ed1-x542.google.com with SMTP id dg9so1472977edb.12 for ; Fri, 16 Oct 2020 02:02:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20150623.gappssmtp.com; s=20150623; h=references:user-agent:from:to:cc:subject:in-reply-to:date :message-id:mime-version; bh=YRalqKr57maWSBCFfKOl28ih/XZdpqUZ21LloKcUJks=; b=RJw96zwU0FQkNGmsV2GHZr0VT571lwKekreZUXepXoEHLq+c8nEGV/Yh2xnNwkWh35 x/EJLppvbeovU3HGvSOjN9+WFqQY81UrIStIrqEVatheU4A9omKh02Y9l1R5OdbPzuqt cyl/Ur77cYpOTUBDgvQf8OHzH+y/5gAs1/72XiCRpGhbDCCU/lPb5vtq46oUqYyyqCzI M0b7P1GJ+TGIyNrSG6M9dtbZ2HJW/HHhbN4MrKS0L2UJ3SKc689zxNT+ZpicuqzpwAz1 nKtT3aDn/mQeHAuzQetX6R7puzox7w4j034Oo30H6nCxs+3vbAa+DHjp0Qs4FNY/M+ut M8vQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:date:message-id:mime-version; bh=YRalqKr57maWSBCFfKOl28ih/XZdpqUZ21LloKcUJks=; b=d4rKSbyg2Hgd5qbfEp6Ti6YelIekPkjVPbOdpIt8V3Yg9dxNyuKg/uAQC2t+qqSD3L 1DmuuYoYVdEeWOl33hp7+ohSHgMFFVLWvVOSODQXD3jJPi7sUDNZY7RqFts1/Roc2FGK 1Q/SuMIZ1pIZLuJyh7vzeXJ6Xg1BhOfU1uhGYVthbcQkZo1+iRPL6iecO7GvVdLp0IcA IoFDaNXFWVgfv7UWGn29XZ3lzZP1NAuGcXyScH/v8WE6mZEomymT1qBmFjBOBkbqN0GA pWgpOxtWanyPS+oK9tJhtxJIfwYdFCMuUshzoRnJ8UxNfCXnYSZWpZZkMPrV7fVWG4Ia pclw== X-Gm-Message-State: AOAM533cwRXVeSy3hrhMNmy554Xpr7XmWTH7dhnGnOws4FXXt0Edrc/a xTTidLiD0PM11QgIfDNmDPMfVA== X-Google-Smtp-Source: ABdhPJxJfdyU0OC1yvdvGDEZ8q85HrAiLG1l1xKb7I8SIW4X4SGJNje80ty/juGeB0gzJ6huReSteg== X-Received: by 2002:aa7:d4d8:: with SMTP id t24mr2702751edr.247.1602838924236; Fri, 16 Oct 2020 02:02:04 -0700 (PDT) Received: from localhost (82-65-169-74.subs.proxad.net. [82.65.169.74]) by smtp.gmail.com with ESMTPSA id a13sm915107edx.53.2020.10.16.02.02.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Oct 2020 02:02:03 -0700 (PDT) References: <20200923123916.1115962-1-jbrunet@baylibre.com> <20201015134628.GA11989@arm.com> <1jlfg7k2ux.fsf@starbuckisacylon.baylibre.com> <20201015142935.GA12516@arm.com> <20201016084428.gthqj25wrvnqjsvz@bogus> User-agent: mu4e 1.3.3; emacs 26.3 From: Jerome Brunet To: Sudeep Holla , Ionela Voinescu Cc: Jassi Brar , Kevin Hilman , linux-amlogic@lists.infradead.org, Da Xue , linux-kernel@vger.kernel.org Subject: Re: [PATCH] mailbox: cancel timer before starting it In-reply-to: <20201016084428.gthqj25wrvnqjsvz@bogus> Date: Fri, 16 Oct 2020 11:02:02 +0200 Message-ID: <1jimbak0hh.fsf@starbuckisacylon.baylibre.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 16 Oct 2020 at 10:44, Sudeep Holla wrote: > On Thu, Oct 15, 2020 at 03:29:35PM +0100, Ionela Voinescu wrote: >> Hi Jerome, >> >> On Thursday 15 Oct 2020 at 15:58:30 (+0200), Jerome Brunet wrote: >> > >> > On Thu 15 Oct 2020 at 15:46, Ionela Voinescu wrote: >> > >> > > Hi guys, >> > > >> > > On Wednesday 23 Sep 2020 at 14:39:16 (+0200), Jerome Brunet wrote: >> > >> 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 >> > >> [...] >> > >> >> > >> Canceling the timer before starting it ensure that the timer callback is >> > >> not running when the timer is started, solving this race condition. >> > >> >> > >> Fixes: 0cc67945ea59 ("mailbox: switch to hrtimer for tx_complete polling") >> > >> Reported-by: Da Xue >> > >> Signed-off-by: Jerome Brunet >> > >> --- >> > >> drivers/mailbox/mailbox.c | 8 ++++++-- >> > >> 1 file changed, 6 insertions(+), 2 deletions(-) >> > >> >> > >> diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c >> > >> index 0b821a5b2db8..34f9ab01caef 100644 >> > >> --- a/drivers/mailbox/mailbox.c >> > >> +++ b/drivers/mailbox/mailbox.c >> > >> @@ -82,9 +82,13 @@ 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 */ >> > >> + if (!err && (chan->txdone_method & TXDONE_BY_POLL)) { >> > >> + /* Disable the timer if already active ... */ >> > >> + hrtimer_cancel(&chan->mbox->poll_hrt); >> > >> + >> > >> + /* ... and kick start it immediately to avoid delays */ >> > >> hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); >> > >> + } >> > >> } >> > >> >> > >> static void tx_tick(struct mbox_chan *chan, int r) >> > > >> > > I've tracked a regression back to this commit. Details to reproduce: >> > >> > Hi Ionela, >> > >> > I don't have access to your platform and I don't get what is going on >> > from the log below. >> > >> > Could you please give us a bit more details about what is going on ? >> > >> >> I'm not familiar with the mailbox subsystem, so the best I can do right >> now is to add Sudeep to Cc, in case this conflicts in some way with the >> ARM MHU patches [1]. >> > > Not it can't be doorbell driver as we use SCPI(old firmware) with upstream > MHU driver as is limiting the number of channels to be used. > >> In the meantime I'll get some traces and get more familiar with the >> code. >> > > I will try that too. BTW, this issue was originally reported on amlogic platforms which also use arm,mhu mailbox driver. 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[82.65.169.74]) by smtp.gmail.com with ESMTPSA id a13sm915107edx.53.2020.10.16.02.02.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Oct 2020 02:02:03 -0700 (PDT) References: <20200923123916.1115962-1-jbrunet@baylibre.com> <20201015134628.GA11989@arm.com> <1jlfg7k2ux.fsf@starbuckisacylon.baylibre.com> <20201015142935.GA12516@arm.com> <20201016084428.gthqj25wrvnqjsvz@bogus> User-agent: mu4e 1.3.3; emacs 26.3 From: Jerome Brunet To: Sudeep Holla , Ionela Voinescu Subject: Re: [PATCH] mailbox: cancel timer before starting it In-reply-to: <20201016084428.gthqj25wrvnqjsvz@bogus> Date: Fri, 16 Oct 2020 11:02:02 +0200 Message-ID: <1jimbak0hh.fsf@starbuckisacylon.baylibre.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201016_050205_465383_40A45E01 X-CRM114-Status: GOOD ( 28.60 ) X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Hilman , Jassi Brar , Da Xue , linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org On Fri 16 Oct 2020 at 10:44, Sudeep Holla wrote: > On Thu, Oct 15, 2020 at 03:29:35PM +0100, Ionela Voinescu wrote: >> Hi Jerome, >> >> On Thursday 15 Oct 2020 at 15:58:30 (+0200), Jerome Brunet wrote: >> > >> > On Thu 15 Oct 2020 at 15:46, Ionela Voinescu wrote: >> > >> > > Hi guys, >> > > >> > > On Wednesday 23 Sep 2020 at 14:39:16 (+0200), Jerome Brunet wrote: >> > >> 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 >> > >> [...] >> > >> >> > >> Canceling the timer before starting it ensure that the timer callback is >> > >> not running when the timer is started, solving this race condition. >> > >> >> > >> Fixes: 0cc67945ea59 ("mailbox: switch to hrtimer for tx_complete polling") >> > >> Reported-by: Da Xue >> > >> Signed-off-by: Jerome Brunet >> > >> --- >> > >> drivers/mailbox/mailbox.c | 8 ++++++-- >> > >> 1 file changed, 6 insertions(+), 2 deletions(-) >> > >> >> > >> diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c >> > >> index 0b821a5b2db8..34f9ab01caef 100644 >> > >> --- a/drivers/mailbox/mailbox.c >> > >> +++ b/drivers/mailbox/mailbox.c >> > >> @@ -82,9 +82,13 @@ 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 */ >> > >> + if (!err && (chan->txdone_method & TXDONE_BY_POLL)) { >> > >> + /* Disable the timer if already active ... */ >> > >> + hrtimer_cancel(&chan->mbox->poll_hrt); >> > >> + >> > >> + /* ... and kick start it immediately to avoid delays */ >> > >> hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); >> > >> + } >> > >> } >> > >> >> > >> static void tx_tick(struct mbox_chan *chan, int r) >> > > >> > > I've tracked a regression back to this commit. Details to reproduce: >> > >> > Hi Ionela, >> > >> > I don't have access to your platform and I don't get what is going on >> > from the log below. >> > >> > Could you please give us a bit more details about what is going on ? >> > >> >> I'm not familiar with the mailbox subsystem, so the best I can do right >> now is to add Sudeep to Cc, in case this conflicts in some way with the >> ARM MHU patches [1]. >> > > Not it can't be doorbell driver as we use SCPI(old firmware) with upstream > MHU driver as is limiting the number of channels to be used. > >> In the meantime I'll get some traces and get more familiar with the >> code. >> > > I will try that too. BTW, this issue was originally reported on amlogic platforms which also use arm,mhu mailbox driver. _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic