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[PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe

Started by"Kweh, Hock Leong" <hock.leong.kweh@intel.com>
First post2016-12-27 04:50 +0100
Last post2016-12-27 06:20 +0100
Articles 6 — 3 participants

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  [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe "Kweh, Hock Leong" <hock.leong.kweh@intel.com> - 2016-12-27 04:50 +0100
    Re: [PATCH] net: stmmac: synchronize stmmac_open and  stmmac_dvr_probe David Miller <davem@davemloft.net> - 2016-12-27 06:00 +0100
      RE: [PATCH] net: stmmac: synchronize stmmac_open and  stmmac_dvr_probe "Kweh, Hock Leong" <hock.leong.kweh@intel.com> - 2016-12-27 06:30 +0100
    Re: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe Florian Fainelli <f.fainelli@gmail.com> - 2016-12-27 06:20 +0100
      RE: [PATCH] net: stmmac: synchronize stmmac_open and  stmmac_dvr_probe "Kweh, Hock Leong" <hock.leong.kweh@intel.com> - 2016-12-27 06:30 +0100
    Re: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe Florian Fainelli <f.fainelli@gmail.com> - 2016-12-27 06:20 +0100

#1547486 — [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe

From"Kweh, Hock Leong" <hock.leong.kweh@intel.com>
Date2016-12-27 04:50 +0100
Subject[PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe
Message-ID<sSQVX-5fn-1@gated-at.bofh.it>
From: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>

If kernel module stmmac driver being loaded after OS booted, there is a
race condition between stmmac_open() and stmmac_mdio_register(), which is
invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as
PHY not found and stmmac_open() failed:
[  473.919358] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
		stmmac_dvr_probe: warning: cannot get CSR clock
[  473.919382] stmmaceth 0000:01:00.0: no reset control found
[  473.919412] stmmac - user ID: 0x10, Synopsys ID: 0x42
[  473.919429] stmmaceth 0000:01:00.0: DMA HW capability register supported
[  473.919436] stmmaceth 0000:01:00.0: RX Checksum Offload Engine supported
[  473.919443] stmmaceth 0000:01:00.0: TX Checksum insertion supported
[  473.919451] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
		Enable RX Mitigation via HW Watchdog Timer
[  473.921395] libphy: PHY stmmac-1:00 not found
[  473.921417] stmmaceth 0000:01:00.0 eth0: Could not attach to PHY
[  473.921427] stmmaceth 0000:01:00.0 eth0: stmmac_open: Cannot attach to
		PHY (error: -19)
[  473.959710] libphy: stmmac: probed
[  473.959724] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 0 IRQ POLL
		(stmmac-1:00) active
[  473.959728] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 1 IRQ POLL
		(stmmac-1:01)
[  473.959731] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 2 IRQ POLL
		(stmmac-1:02)
[  473.959734] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 3 IRQ POLL
		(stmmac-1:03)

The resolution used wait_for_completion_interruptible() to synchronize
stmmac_open() and stmmac_dvr_probe() to prevent the race condition
happening.

Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h      |    1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |   10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index eab04ae..5daf8a5 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -131,6 +131,7 @@ struct stmmac_priv {
 	u32 rx_tail_addr;
 	u32 tx_tail_addr;
 	u32 mss;
+	struct completion probe_done;
 
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *dbgfs_dir;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index bb40382..28e85f6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1770,6 +1770,14 @@ static int stmmac_open(struct net_device *dev)
 	struct stmmac_priv *priv = netdev_priv(dev);
 	int ret;
 
+	ret = wait_for_completion_interruptible(&priv->probe_done);
+	if (ret) {
+		netdev_err(priv->dev,
+			   "%s: Interrupted while waiting probe completion\n",
+			   __func__);
+		return ret;
+	}
+
 	stmmac_check_ether_addr(priv);
 
 	if (priv->hw->pcs != STMMAC_PCS_RGMII &&
@@ -3226,6 +3234,7 @@ int stmmac_dvr_probe(struct device *device,
 	priv = netdev_priv(ndev);
 	priv->device = device;
 	priv->dev = ndev;
+	init_completion(&priv->probe_done);
 
 	stmmac_set_ethtool_ops(ndev);
 	priv->pause = pause;
@@ -3372,6 +3381,7 @@ int stmmac_dvr_probe(struct device *device,
 		}
 	}
 
+	complete_all(&priv->probe_done);
 	return 0;
 
 error_mdio_register:
-- 
1.7.9.5

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#1547493 — Re: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe

FromDavid Miller <davem@davemloft.net>
Date2016-12-27 06:00 +0100
SubjectRe: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe
Message-ID<sSS1H-5Se-3@gated-at.bofh.it>
In reply to#1547486
From: "Kweh, Hock Leong"	<hock.leong.kweh@intel.com>
Date: Tue, 27 Dec 2016 19:44:59 +0800

> From: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>
> 
> If kernel module stmmac driver being loaded after OS booted, there is a
> race condition between stmmac_open() and stmmac_mdio_register(), which is
> invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as
> PHY not found and stmmac_open() failed:
 ...
> The resolution used wait_for_completion_interruptible() to synchronize
> stmmac_open() and stmmac_dvr_probe() to prevent the race condition
> happening.
> 
> Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@intel.com>

The proper thing to do is to make sure register_netdevice() is not
invoked until it is %100 safe to call stmmac_open().

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#1547498 — RE: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe

From"Kweh, Hock Leong" <hock.leong.kweh@intel.com>
Date2016-12-27 06:30 +0100
SubjectRE: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe
Message-ID<sSSuJ-6m6-1@gated-at.bofh.it>
In reply to#1547493
> -----Original Message-----
> From: David Miller [mailto:davem@davemloft.net]
> Sent: Tuesday, December 27, 2016 12:55 PM
> To: Kweh, Hock Leong <hock.leong.kweh@intel.com>
> Cc: Joao.Pinto@synopsys.com; peppe.cavallaro@st.com;
> seraphin.bonnaffe@st.com; alexandre.torgue@gmail.com;
> manabian@gmail.com; niklas.cassel@axis.com; johan@kernel.org;
> pavel@ucw.cz; Ong, Boon Leong <boon.leong.ong@intel.com>;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Voon, Weifeng
> <weifeng.voon@intel.com>; lars.persson@axis.com
> Subject: Re: [PATCH] net: stmmac: synchronize stmmac_open and
> stmmac_dvr_probe
> 
> From: "Kweh, Hock Leong"	<hock.leong.kweh@intel.com>
> Date: Tue, 27 Dec 2016 19:44:59 +0800
> 
> > From: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>
> >
> > If kernel module stmmac driver being loaded after OS booted, there is a
> > race condition between stmmac_open() and stmmac_mdio_register(), which is
> > invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as
> > PHY not found and stmmac_open() failed:
>  ...
> > The resolution used wait_for_completion_interruptible() to synchronize
> > stmmac_open() and stmmac_dvr_probe() to prevent the race condition
> > happening.
> >
> > Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@intel.com>
> 
> The proper thing to do is to make sure register_netdevice() is not
> invoked until it is %100 safe to call stmmac_open().

Noted & thanks. Will look into it.

Regards,
Wilson

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#1547496

FromFlorian Fainelli <f.fainelli@gmail.com>
Date2016-12-27 06:20 +0100
Message-ID<sSSl3-6g4-1@gated-at.bofh.it>
In reply to#1547486

On 12/26/2016 09:10 PM, Florian Fainelli wrote:
> 
> 
> On 12/27/2016 03:44 AM, Kweh, Hock Leong wrote:
>> From: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>
>>
>> If kernel module stmmac driver being loaded after OS booted, there is a
>> race condition between stmmac_open() and stmmac_mdio_register(), which is
>> invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as
>> PHY not found and stmmac_open() failed:
>> [  473.919358] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
>> 		stmmac_dvr_probe: warning: cannot get CSR clock
>> [  473.919382] stmmaceth 0000:01:00.0: no reset control found
>> [  473.919412] stmmac - user ID: 0x10, Synopsys ID: 0x42
>> [  473.919429] stmmaceth 0000:01:00.0: DMA HW capability register supported
>> [  473.919436] stmmaceth 0000:01:00.0: RX Checksum Offload Engine supported
>> [  473.919443] stmmaceth 0000:01:00.0: TX Checksum insertion supported
>> [  473.919451] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
>> 		Enable RX Mitigation via HW Watchdog Timer
>> [  473.921395] libphy: PHY stmmac-1:00 not found
>> [  473.921417] stmmaceth 0000:01:00.0 eth0: Could not attach to PHY
>> [  473.921427] stmmaceth 0000:01:00.0 eth0: stmmac_open: Cannot attach to
>> 		PHY (error: -19)
>> [  473.959710] libphy: stmmac: probed
>> [  473.959724] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 0 IRQ POLL
>> 		(stmmac-1:00) active
>> [  473.959728] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 1 IRQ POLL
>> 		(stmmac-1:01)
>> [  473.959731] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 2 IRQ POLL
>> 		(stmmac-1:02)
>> [  473.959734] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 3 IRQ POLL
>> 		(stmmac-1:03)
>>
>> The resolution used wait_for_completion_interruptible() to synchronize
>> stmmac_open() and stmmac_dvr_probe() to prevent the race condition
>> happening.
> 
> The proper fix for this would be to have register_netdev() be the last
> thing done in stmmac_drv_probe(), whereas right now, the last thing done
> is stmmac_mdio_register(), leading the window you are seeing here, where
> the network interface can be open prior to all resources being set up,
> including, but not limited to MDIO devices.

Something like the following untested patch should plug this race:

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index bb40382e205d..5910ea51f8f6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3339,13 +3339,6 @@ int stmmac_dvr_probe(struct device *device,

        spin_lock_init(&priv->lock);

-       ret = register_netdev(ndev);
-       if (ret) {
-               netdev_err(priv->dev, "%s: ERROR %i registering the
device\n",
-                          __func__, ret);
-               goto error_netdev_register;
-       }
-
        /* If a specific clk_csr value is passed from the platform
         * this means that the CSR Clock Range selection cannot be
         * changed at run-time and it is fixed. Viceversa the driver'll
try to
@@ -3372,11 +3365,14 @@ int stmmac_dvr_probe(struct device *device,
                }
        }

-       return 0;
+       ret = register_netdev(ndev);
+       if (ret)
+               netdev_err(priv->dev, "%s: ERROR %i registering the
device\n",
+                          __func__, ret);
+
+       return ret;

 error_mdio_register:
-       unregister_netdev(ndev);
-error_netdev_register:
        netif_napi_del(&priv->napi);
 error_hw_init:
        clk_disable_unprepare(priv->pclk);

-- 
Florian

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#1547499 — RE: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe

From"Kweh, Hock Leong" <hock.leong.kweh@intel.com>
Date2016-12-27 06:30 +0100
SubjectRE: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe
Message-ID<sSSuJ-6m6-5@gated-at.bofh.it>
In reply to#1547496
> -----Original Message-----
> From: Florian Fainelli [mailto:f.fainelli@gmail.com]
> Sent: Tuesday, December 27, 2016 1:14 PM
> To: Kweh, Hock Leong <hock.leong.kweh@intel.com>; David S. Miller
> <davem@davemloft.net>; Joao Pinto <Joao.Pinto@synopsys.com>; Giuseppe
> CAVALLARO <peppe.cavallaro@st.com>; seraphin.bonnaffe@st.com
> Cc: Alexandre TORGUE <alexandre.torgue@gmail.com>; Joachim Eastwood
> <manabian@gmail.com>; Niklas Cassel <niklas.cassel@axis.com>; Johan Hovold
> <johan@kernel.org>; pavel@ucw.cz; Ong, Boon Leong
> <boon.leong.ong@intel.com>; netdev <netdev@vger.kernel.org>; LKML <linux-
> kernel@vger.kernel.org>; Voon, Weifeng <weifeng.voon@intel.com>; Lars
> Persson <lars.persson@axis.com>
> Subject: Re: [PATCH] net: stmmac: synchronize stmmac_open and
> stmmac_dvr_probe
> 
> 
> 
> On 12/26/2016 09:10 PM, Florian Fainelli wrote:
> >
> >
> > On 12/27/2016 03:44 AM, Kweh, Hock Leong wrote:
> >> From: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>
> >>
> >> If kernel module stmmac driver being loaded after OS booted, there is a
> >> race condition between stmmac_open() and stmmac_mdio_register(), which
> is
> >> invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as
> >> PHY not found and stmmac_open() failed:
> >> [  473.919358] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
> >> 		stmmac_dvr_probe: warning: cannot get CSR clock
> >> [  473.919382] stmmaceth 0000:01:00.0: no reset control found
> >> [  473.919412] stmmac - user ID: 0x10, Synopsys ID: 0x42
> >> [  473.919429] stmmaceth 0000:01:00.0: DMA HW capability register
> supported
> >> [  473.919436] stmmaceth 0000:01:00.0: RX Checksum Offload Engine
> supported
> >> [  473.919443] stmmaceth 0000:01:00.0: TX Checksum insertion supported
> >> [  473.919451] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
> >> 		Enable RX Mitigation via HW Watchdog Timer
> >> [  473.921395] libphy: PHY stmmac-1:00 not found
> >> [  473.921417] stmmaceth 0000:01:00.0 eth0: Could not attach to PHY
> >> [  473.921427] stmmaceth 0000:01:00.0 eth0: stmmac_open: Cannot attach
> to
> >> 		PHY (error: -19)
> >> [  473.959710] libphy: stmmac: probed
> >> [  473.959724] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 0 IRQ POLL
> >> 		(stmmac-1:00) active
> >> [  473.959728] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 1 IRQ POLL
> >> 		(stmmac-1:01)
> >> [  473.959731] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 2 IRQ POLL
> >> 		(stmmac-1:02)
> >> [  473.959734] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 3 IRQ POLL
> >> 		(stmmac-1:03)
> >>
> >> The resolution used wait_for_completion_interruptible() to synchronize
> >> stmmac_open() and stmmac_dvr_probe() to prevent the race condition
> >> happening.
> >
> > The proper fix for this would be to have register_netdev() be the last
> > thing done in stmmac_drv_probe(), whereas right now, the last thing done
> > is stmmac_mdio_register(), leading the window you are seeing here, where
> > the network interface can be open prior to all resources being set up,
> > including, but not limited to MDIO devices.
> 
> Something like the following untested patch should plug this race:
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index bb40382e205d..5910ea51f8f6 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -3339,13 +3339,6 @@ int stmmac_dvr_probe(struct device *device,
> 
>         spin_lock_init(&priv->lock);
> 
> -       ret = register_netdev(ndev);
> -       if (ret) {
> -               netdev_err(priv->dev, "%s: ERROR %i registering the
> device\n",
> -                          __func__, ret);
> -               goto error_netdev_register;
> -       }
> -
>         /* If a specific clk_csr value is passed from the platform
>          * this means that the CSR Clock Range selection cannot be
>          * changed at run-time and it is fixed. Viceversa the driver'll
> try to
> @@ -3372,11 +3365,14 @@ int stmmac_dvr_probe(struct device *device,
>                 }
>         }
> 
> -       return 0;
> +       ret = register_netdev(ndev);
> +       if (ret)
> +               netdev_err(priv->dev, "%s: ERROR %i registering the
> device\n",
> +                          __func__, ret);
> +
> +       return ret;
> 
>  error_mdio_register:
> -       unregister_netdev(ndev);
> -error_netdev_register:
>         netif_napi_del(&priv->napi);
>  error_hw_init:
>         clk_disable_unprepare(priv->pclk);
> 
> --
> Florian

Thanks. Will try out to confirm.

Regards,
Wilson

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#1547497

FromFlorian Fainelli <f.fainelli@gmail.com>
Date2016-12-27 06:20 +0100
Message-ID<sSSl3-6g4-3@gated-at.bofh.it>
In reply to#1547486

On 12/27/2016 03:44 AM, Kweh, Hock Leong wrote:
> From: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>
> 
> If kernel module stmmac driver being loaded after OS booted, there is a
> race condition between stmmac_open() and stmmac_mdio_register(), which is
> invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as
> PHY not found and stmmac_open() failed:
> [  473.919358] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
> 		stmmac_dvr_probe: warning: cannot get CSR clock
> [  473.919382] stmmaceth 0000:01:00.0: no reset control found
> [  473.919412] stmmac - user ID: 0x10, Synopsys ID: 0x42
> [  473.919429] stmmaceth 0000:01:00.0: DMA HW capability register supported
> [  473.919436] stmmaceth 0000:01:00.0: RX Checksum Offload Engine supported
> [  473.919443] stmmaceth 0000:01:00.0: TX Checksum insertion supported
> [  473.919451] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized):
> 		Enable RX Mitigation via HW Watchdog Timer
> [  473.921395] libphy: PHY stmmac-1:00 not found
> [  473.921417] stmmaceth 0000:01:00.0 eth0: Could not attach to PHY
> [  473.921427] stmmaceth 0000:01:00.0 eth0: stmmac_open: Cannot attach to
> 		PHY (error: -19)
> [  473.959710] libphy: stmmac: probed
> [  473.959724] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 0 IRQ POLL
> 		(stmmac-1:00) active
> [  473.959728] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 1 IRQ POLL
> 		(stmmac-1:01)
> [  473.959731] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 2 IRQ POLL
> 		(stmmac-1:02)
> [  473.959734] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 3 IRQ POLL
> 		(stmmac-1:03)
> 
> The resolution used wait_for_completion_interruptible() to synchronize
> stmmac_open() and stmmac_dvr_probe() to prevent the race condition
> happening.

The proper fix for this would be to have register_netdev() be the last
thing done in stmmac_drv_probe(), whereas right now, the last thing done
is stmmac_mdio_register(), leading the window you are seeing here, where
the network interface can be open prior to all resources being set up,
including, but not limited to MDIO devices.
-- 
Florian

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