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From: Jose Abreu <Jose.Abreu@synopsys.com>
To: Jon Hunter <jonathanh@nvidia.com>,
	Jose Abreu <Jose.Abreu@synopsys.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Cc: Joao Pinto <Joao.Pinto@synopsys.com>,
	"David S . Miller" <davem@davemloft.net>,
	Giuseppe Cavallaro <peppe.cavallaro@st.com>,
	"Alexandre Torgue" <alexandre.torgue@st.com>,
	Russell King <linux@armlinux.org.uk>,
	Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"Heiner Kallweit" <hkallweit1@gmail.com>,
	linux-tegra <linux-tegra@vger.kernel.org>
Subject: RE: [PATCH net-next 3/3] net: stmmac: Convert to phylink and remove phylib logic
Date: Tue, 25 Jun 2019 11:25:40 +0000
Message-ID: <78EB27739596EE489E55E81C33FEC33A0B9D76C2@DE02WEMBXB.internal.synopsys.com> (raw)
In-Reply-To: <113f37a2-c37f-cdb5-5194-4361d949258a@nvidia.com>

From: Jon Hunter <jonathanh@nvidia.com>

> I have been looking at this a bit closer and I can see the problem. What
> happens is that ...
> 
> 1. stmmac_mac_link_up() is called and priv->eee_active is set to false
> 2. stmmac_eee_init() is called but because priv->eee_active is false,
>    timer_setup() for eee_ctrl_timer is never called.
> 3. stmmac_eee_init() returns true and so then priv->eee_enabled is set 
>    to true.
> 4. When stmmac_tx_clean() is called because priv->eee_enabled is set to    
>    true, mod_timer() is called for the eee_ctrl_timer, but because 
>    timer_setup() was never called, we hit the BUG defined at
>    kernel/time/timer.c:952, because no function is defined for the 
>    timer.
> 
> The following fixes it for me ...
> 
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -399,10 +399,13 @@ bool stmmac_eee_init(struct stmmac_priv *priv)
>         mutex_lock(&priv->lock);
>  
>         /* Check if it needs to be deactivated */
> -       if (!priv->eee_active && priv->eee_enabled) {
> -               netdev_dbg(priv->dev, "disable EEE\n");
> -               del_timer_sync(&priv->eee_ctrl_timer);
> -               stmmac_set_eee_timer(priv, priv->hw, 0, tx_lpi_timer);
> +       if (!priv->eee_active) {
> +               if (priv->eee_enabled) {
> +                       netdev_dbg(priv->dev, "disable EEE\n");
> +                       del_timer_sync(&priv->eee_ctrl_timer);
> +                       stmmac_set_eee_timer(priv, priv->hw, 0, tx_lpi_timer);
> +               }
> +               mutex_unlock(&priv->lock);
>                 return false;
>         }
> 
> It also looks like you have a potention deadlock in the current code
> because in the case of if (!priv->eee_active && priv->eee_enabled)
> you don't unlock the mutex. The above fixes this as well. I can send a
> formal patch if this looks correct. 

Thanks for looking into this! The fix looks correct so if you could 
submit a patch it would be great!

Thanks,
Jose Miguel Abreu

  reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-11 15:18 [PATCH net-next 0/3] net: stmmac: Convert to phylink Jose Abreu
2019-06-11 15:18 ` [PATCH net-next 1/3] net: stmmac: Prepare to convert " Jose Abreu
2019-06-11 15:18 ` [PATCH net-next 2/3] net: stmmac: Start adding phylink support Jose Abreu
2019-06-11 15:35   ` Russell King - ARM Linux admin
2019-06-11 15:40     ` Jose Abreu
2019-06-11 15:18 ` [PATCH net-next 3/3] net: stmmac: Convert to phylink and remove phylib logic Jose Abreu
2019-06-18  9:30   ` Jon Hunter
2019-06-18  9:35     ` Jose Abreu
2019-06-18  9:42       ` Jon Hunter
2019-06-18  9:46         ` Jose Abreu
2019-06-18 10:18           ` Jon Hunter
2019-06-18 15:20             ` Jon Hunter
2019-06-18 19:44               ` Jon Hunter
2019-06-20 14:05                 ` Jon Hunter
2019-06-25  7:37                   ` Jose Abreu
2019-06-25 11:10                     ` Jon Hunter
2019-06-25 11:25                       ` Jose Abreu [this message]
2019-06-13 21:02 ` [PATCH net-next 0/3] net: stmmac: Convert to phylink David Miller
2019-06-14 13:40 ` Corentin Labbe
2019-06-14 14:45   ` Jose Abreu
2019-07-22 12:42 ` Ondřej Jirman
2019-07-22 13:28   ` Jose Abreu
2019-07-22 13:40     ` Andrew Lunn
2019-07-22 13:58       ` Jose Abreu
2019-07-22 14:19         ` Andrew Lunn
2019-07-22 14:26           ` Jose Abreu
2019-07-22 14:39             ` Ondřej Jirman
2019-07-23  9:36               ` Jose Abreu
2019-07-22 13:49     ` Ondřej Jirman

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