From: Francesco Dolcini <francesco.dolcini@toradex.com>
To: "Marc Kleine-Budde" <mkl@pengutronix.de>,
"Csókás Bence" <csokas.bence@prolan.hu>
Cc: netdev@vger.kernel.org, Andrew Lunn <andrew@lunn.ch>,
Richard Cochran <richardcochran@gmail.com>,
kernel@pengutronix.de,
Francesco Dolcini <francesco.dolcini@toradex.com>,
Jakub Kicinski <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH v2] net: fec: Use a spinlock to guard `fep->ptp_clk_on`
Date: Fri, 9 Sep 2022 15:56:33 +0200 [thread overview]
Message-ID: <20220909135633.GA219857@francesco-nb.int.toradex.com> (raw)
In-Reply-To: <20220907143915.5w65kainpykfobte@pengutronix.de>
On Wed, Sep 07, 2022 at 04:39:15PM +0200, Marc Kleine-Budde wrote:
> On 05.09.2022 09:38:04, Marc Kleine-Budde wrote:
> > On 9/1/22 4:04 PM, Csókás Bence wrote:
> > > Mutexes cannot be taken in a non-preemptible context,
> > > causing a panic in `fec_ptp_save_state()`. Replacing
> > > `ptp_clk_mutex` by `tmreg_lock` fixes this.
> >
> > I was on holidays, but this doesn't look good.
>
> Does anyone care to fix this? Csókás?
I do care, however I do not really have resources for anything better than
reverting both of the problematic commits.
If we do not have a fix, I guess this is the only way. Csókás?
For some reason when I tested on imx6 :-( I had no warning, now the
change was merged and while doing a quick test on a imx7
I got new issues.
[ 37.061582] ========================================================
[ 37.070203] WARNING: possible irq lock inversion dependency detected
[ 37.078847] 6.0.0-rc4-00137-g506357871c18 #3 Tainted: G W
[ 37.087944] --------------------------------------------------------
[ 37.096615] systemd/580 just changed the state of lock:
[ 37.104160] c218f2a4 (&dev->tx_global_lock){+.-.}-{2:2}, at: dev_watchdog+0x18/0x2c4
[ 37.116691] but this lock took another, SOFTIRQ-unsafe lock in the past:
[ 37.125896] (&fep->tmreg_lock){+.+.}-{2:2}
[ 37.125921]
[ 37.125921]
[ 37.125921] and interrupts could create inverse lock ordering between them.
[ 37.125921]
[ 37.153018]
[ 37.153018] other info that might help us debug this:
[ 37.163824] Possible interrupt unsafe locking scenario:
[ 37.163824]
[ 37.174714] CPU0 CPU1
[ 37.181215] ---- ----
[ 37.187631] lock(&fep->tmreg_lock);
[ 37.193110] local_irq_disable();
[ 37.200841] lock(&dev->tx_global_lock);
[ 37.209153] lock(&fep->tmreg_lock);
[ 37.217061] <Interrupt>
[ 37.221328] lock(&dev->tx_global_lock);
[ 37.227167]
[ 37.227167] *** DEADLOCK ***
that just goes away reverting this patch.
Francesco
next prev parent reply other threads:[~2022-09-09 13:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 14:04 [PATCH v2] net: fec: Use a spinlock to guard `fep->ptp_clk_on` Csókás Bence
2022-09-01 15:04 ` Francesco Dolcini
2022-09-02 7:18 ` Csókás Bence
2022-09-01 16:26 ` Florian Fainelli
2022-09-02 7:35 ` Csókás Bence
2022-09-02 15:47 ` Florian Fainelli
2022-09-02 17:04 ` Francesco Dolcini
2022-09-03 4:30 ` patchwork-bot+netdevbpf
2022-09-05 7:38 ` Marc Kleine-Budde
2022-09-07 14:39 ` Marc Kleine-Budde
2022-09-09 13:56 ` Francesco Dolcini [this message]
2022-09-10 17:08 ` Csókás Bence
2022-09-14 14:53 ` [REGRESSION] " Guenter Roeck
2022-09-18 18:59 ` [REGRESSION] Re: [PATCH v2] net: fec: Use a spinlock to guard `fep->ptp_clk_on` #forregzbot Thorsten Leemhuis
2022-09-22 10:58 ` Thorsten Leemhuis
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