Patchwork [1/1,v2,net] net: fec: fix kernel oops when plug/unplug cable many times

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Submitter Frank Li
Date April 28, 2013, 3:08 a.m.
Message ID <1367118508-12340-1-git-send-email-Frank.Li@freescale.com>
Download mbox | patch
Permalink /patch/240236/
State Changes Requested
Delegated to: David Miller
Headers show

Comments

Frank Li - April 28, 2013, 3:08 a.m.
reproduce steps
 1. flood ping from other machine
 	ping -f -s 41000 IP
 2. run below script
    while [ 1 ]; do ethtool -s eth0 autoneg off;
    sleep 3;ethtool -s eth0 autoneg on; sleep 4; done;

You can see oops in one hour.

The reason is fec_restart clear BD but NAPI may use it.
The solution is disable NAPI and stop xmit when reset BD.
disable NAPI may sleep, so fec_restart can't be call in
atomic context.

Signed-off-by: Frank Li <Frank.Li@freescale.com>
---

Change from V1 to V2
	Add netif_tx_lock(ndev) to avoid xmit runing when reset hardware	

 drivers/net/ethernet/freescale/fec.c |   41 +++++++++++++++++++++++++++++-----
 drivers/net/ethernet/freescale/fec.h |    3 +-
 2 files changed, 37 insertions(+), 7 deletions(-)
Lucas Stach - April 29, 2013, 1:47 p.m.
Hi Frank,

Am Sonntag, den 28.04.2013, 11:08 +0800 schrieb Frank Li:
> reproduce steps
>  1. flood ping from other machine
>  	ping -f -s 41000 IP
>  2. run below script
>     while [ 1 ]; do ethtool -s eth0 autoneg off;
>     sleep 3;ethtool -s eth0 autoneg on; sleep 4; done;
> 
> You can see oops in one hour.
> 
> The reason is fec_restart clear BD but NAPI may use it.
> The solution is disable NAPI and stop xmit when reset BD.
> disable NAPI may sleep, so fec_restart can't be call in
> atomic context.
> 
> Signed-off-by: Frank Li <Frank.Li@freescale.com>
> ---
> 
> Change from V1 to V2
> 	Add netif_tx_lock(ndev) to avoid xmit runing when reset hardware	
> 
>  drivers/net/ethernet/freescale/fec.c |   41 +++++++++++++++++++++++++++++-----
>  drivers/net/ethernet/freescale/fec.h |    3 +-
>  2 files changed, 37 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
> index 73195f6..d140b50 100644
> --- a/drivers/net/ethernet/freescale/fec.c
> +++ b/drivers/net/ethernet/freescale/fec.c
> @@ -403,6 +403,12 @@ fec_restart(struct net_device *ndev, int duplex)
>  	const struct platform_device_id *id_entry =
>  				platform_get_device_id(fep->pdev);
>  	int i;
> +	if (netif_running(ndev)) {
> +		napi_disable(&fep->napi);
> +		netif_stop_queue(ndev);
> +		netif_tx_lock(ndev);
> +	}
> +
>  	u32 temp_mac[2];
>  	u32 rcntl = OPT_FRAME_SIZE | 0x04;
>  	u32 ecntl = 0x2; /* ETHEREN */
> @@ -559,6 +565,12 @@ fec_restart(struct net_device *ndev, int duplex)
>  
>  	/* Enable interrupts we wish to service */
>  	writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
> +
> +	if (netif_running(ndev)) {
> +		napi_enable(&fep->napi);
> +		netif_wake_queue(ndev);
> +		netif_tx_unlock(ndev);
> +	}
>  }
>  
>  static void
> @@ -598,8 +610,20 @@ fec_timeout(struct net_device *ndev)
>  
>  	ndev->stats.tx_errors++;
>  
> -	fec_restart(ndev, fep->full_duplex);
> -	netif_wake_queue(ndev);
> +	fep->timeout = 1;
> +	schedule_delayed_work(&fep->delay_work, msecs_to_jiffies(1));
> +}

Why are you using delayed work here? I don't see a reason why we would
like to defer execution here. Just use schedule_work().

> +
> +static void fec_enet_work(struct work_struct *work)
> +{
> +	struct fec_enet_private *fep =
> +		container_of(work, struct fec_enet_private, delay_work.work);
> +
> +	if (fep->timeout) {
> +		fep->timeout = 0;
> +		fec_restart(fep->netdev, fep->full_duplex);
> +		netif_wake_queue(fep->netdev);
> +	}
>  }
>  
>  static void
> @@ -996,9 +1020,6 @@ static void fec_enet_adjust_link(struct net_device *ndev)
>  			status_change = 1;
>  		}
>  
> -		/* if any of the above changed restart the FEC */
> -		if (status_change)
> -			fec_restart(ndev, phy_dev->duplex);
>  	} else {
>  		if (fep->link) {
>  			fec_stop(ndev);
> @@ -1010,8 +1031,14 @@ static void fec_enet_adjust_link(struct net_device *ndev)
>  spin_unlock:
>  	spin_unlock_irqrestore(&fep->hw_lock, flags);
>  
> -	if (status_change)
> +	if (status_change) {
> +		/* if any of the above changed restart the FEC,
> +		 * fec_restart may sleep. can't call it in spin_lock
> +		 */
> +		if (phy_dev->link)
> +			fec_restart(ndev, phy_dev->duplex);
>  		phy_print_status(phy_dev);
> +	}
>  }

Don't complicate things unnecessarily. Just put a patch in front of this
one to remove the spinlock. As you removed it already from the RX and TX
paths it doesn't protect anything anymore.

>  
>  static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
> @@ -1882,6 +1909,7 @@ fec_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto failed_register;
>  
> +	INIT_DELAYED_WORK(&fep->delay_work, fec_enet_work);
>  	return 0;
>  
>  failed_register:
> @@ -1918,6 +1946,7 @@ fec_drv_remove(struct platform_device *pdev)
>  	struct resource *r;
>  	int i;
>  
> +	cancel_delayed_work_sync(&fep->delay_work);
>  	unregister_netdev(ndev);
>  	fec_enet_mii_remove(fep);
>  	del_timer_sync(&fep->time_keep);
> diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
> index eb43729..a367b21 100644
> --- a/drivers/net/ethernet/freescale/fec.h
> +++ b/drivers/net/ethernet/freescale/fec.h
> @@ -260,7 +260,8 @@ struct fec_enet_private {
>  	int hwts_rx_en;
>  	int hwts_tx_en;
>  	struct timer_list time_keep;
> -
> +	struct delayed_work delay_work;
> +	int timeout;
>  };
>  
>  void fec_ptp_init(struct net_device *ndev, struct platform_device *pdev);
David Miller - April 30, 2013, 7:35 p.m.
From: Frank Li <Frank.Li@freescale.com>
Date: Sun, 28 Apr 2013 11:08:28 +0800

> @@ -403,6 +403,12 @@ fec_restart(struct net_device *ndev, int duplex)
>  	const struct platform_device_id *id_entry =
>  				platform_get_device_id(fep->pdev);
>  	int i;
> +	if (netif_running(ndev)) {
> +		napi_disable(&fep->napi);
> +		netif_stop_queue(ndev);
> +		netif_tx_lock(ndev);
> +	}
> +
>  	u32 temp_mac[2];
>  	u32 rcntl = OPT_FRAME_SIZE | 0x04;
>  	u32 ecntl = 0x2; /* ETHEREN */

Please don't put real statements in the middle of function variable
declarations.

Thanks.
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Frank Li - May 2, 2013, 2:08 a.m.
2013/4/29 Lucas Stach <l.stach@pengutronix.de>:
> Hi Frank,
>
> Am Sonntag, den 28.04.2013, 11:08 +0800 schrieb Frank Li:
>> reproduce steps
>>  1. flood ping from other machine
>>       ping -f -s 41000 IP
>>  2. run below script
>>     while [ 1 ]; do ethtool -s eth0 autoneg off;
>>     sleep 3;ethtool -s eth0 autoneg on; sleep 4; done;
>>
>> You can see oops in one hour.
>>
>> The reason is fec_restart clear BD but NAPI may use it.
>> The solution is disable NAPI and stop xmit when reset BD.
>> disable NAPI may sleep, so fec_restart can't be call in
>> atomic context.
>>
>> Signed-off-by: Frank Li <Frank.Li@freescale.com>
>> ---
>>
>> Change from V1 to V2
>>       Add netif_tx_lock(ndev) to avoid xmit runing when reset hardware
>>
>>  drivers/net/ethernet/freescale/fec.c |   41 +++++++++++++++++++++++++++++-----
>>  drivers/net/ethernet/freescale/fec.h |    3 +-
>>  2 files changed, 37 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
>> index 73195f6..d140b50 100644
>> --- a/drivers/net/ethernet/freescale/fec.c
>> +++ b/drivers/net/ethernet/freescale/fec.c
>> @@ -403,6 +403,12 @@ fec_restart(struct net_device *ndev, int duplex)
>>       const struct platform_device_id *id_entry =
>>                               platform_get_device_id(fep->pdev);
>>       int i;
>> +     if (netif_running(ndev)) {
>> +             napi_disable(&fep->napi);
>> +             netif_stop_queue(ndev);
>> +             netif_tx_lock(ndev);
>> +     }
>> +
>>       u32 temp_mac[2];
>>       u32 rcntl = OPT_FRAME_SIZE | 0x04;
>>       u32 ecntl = 0x2; /* ETHEREN */
>> @@ -559,6 +565,12 @@ fec_restart(struct net_device *ndev, int duplex)
>>
>>       /* Enable interrupts we wish to service */
>>       writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
>> +
>> +     if (netif_running(ndev)) {
>> +             napi_enable(&fep->napi);
>> +             netif_wake_queue(ndev);
>> +             netif_tx_unlock(ndev);
>> +     }
>>  }
>>
>>  static void
>> @@ -598,8 +610,20 @@ fec_timeout(struct net_device *ndev)
>>
>>       ndev->stats.tx_errors++;
>>
>> -     fec_restart(ndev, fep->full_duplex);
>> -     netif_wake_queue(ndev);
>> +     fep->timeout = 1;
>> +     schedule_delayed_work(&fep->delay_work, msecs_to_jiffies(1));
>> +}
>
> Why are you using delayed work here? I don't see a reason why we would
> like to defer execution here. Just use schedule_work().
>

There are a silicon bug, which need delay work to workaround it.
So we can share a delay work in future.

>> +
>> +static void fec_enet_work(struct work_struct *work)
>> +{
>> +     struct fec_enet_private *fep =
>> +             container_of(work, struct fec_enet_private, delay_work.work);
>> +
>> +     if (fep->timeout) {
>> +             fep->timeout = 0;
>> +             fec_restart(fep->netdev, fep->full_duplex);
>> +             netif_wake_queue(fep->netdev);
>> +     }
>>  }
>>
>>  static void
>> @@ -996,9 +1020,6 @@ static void fec_enet_adjust_link(struct net_device *ndev)
>>                       status_change = 1;
>>               }
>>
>> -             /* if any of the above changed restart the FEC */
>> -             if (status_change)
>> -                     fec_restart(ndev, phy_dev->duplex);
>>       } else {
>>               if (fep->link) {
>>                       fec_stop(ndev);
>> @@ -1010,8 +1031,14 @@ static void fec_enet_adjust_link(struct net_device *ndev)
>>  spin_unlock:
>>       spin_unlock_irqrestore(&fep->hw_lock, flags);
>>
>> -     if (status_change)
>> +     if (status_change) {
>> +             /* if any of the above changed restart the FEC,
>> +              * fec_restart may sleep. can't call it in spin_lock
>> +              */
>> +             if (phy_dev->link)
>> +                     fec_restart(ndev, phy_dev->duplex);
>>               phy_print_status(phy_dev);
>> +     }
>>  }
>
> Don't complicate things unnecessarily. Just put a patch in front of this
> one to remove the spinlock. As you removed it already from the RX and TX
> paths it doesn't protect anything anymore.
>
>>
>>  static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
>> @@ -1882,6 +1909,7 @@ fec_probe(struct platform_device *pdev)
>>       if (ret)
>>               goto failed_register;
>>
>> +     INIT_DELAYED_WORK(&fep->delay_work, fec_enet_work);
>>       return 0;
>>
>>  failed_register:
>> @@ -1918,6 +1946,7 @@ fec_drv_remove(struct platform_device *pdev)
>>       struct resource *r;
>>       int i;
>>
>> +     cancel_delayed_work_sync(&fep->delay_work);
>>       unregister_netdev(ndev);
>>       fec_enet_mii_remove(fep);
>>       del_timer_sync(&fep->time_keep);
>> diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
>> index eb43729..a367b21 100644
>> --- a/drivers/net/ethernet/freescale/fec.h
>> +++ b/drivers/net/ethernet/freescale/fec.h
>> @@ -260,7 +260,8 @@ struct fec_enet_private {
>>       int hwts_rx_en;
>>       int hwts_tx_en;
>>       struct timer_list time_keep;
>> -
>> +     struct delayed_work delay_work;
>> +     int timeout;
>>  };
>>
>>  void fec_ptp_init(struct net_device *ndev, struct platform_device *pdev);
>
> --
> Pengutronix e.K.                           | Lucas Stach                 |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |
> Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-5076 |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
>
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Patch

diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
index 73195f6..d140b50 100644
--- a/drivers/net/ethernet/freescale/fec.c
+++ b/drivers/net/ethernet/freescale/fec.c
@@ -403,6 +403,12 @@  fec_restart(struct net_device *ndev, int duplex)
 	const struct platform_device_id *id_entry =
 				platform_get_device_id(fep->pdev);
 	int i;
+	if (netif_running(ndev)) {
+		napi_disable(&fep->napi);
+		netif_stop_queue(ndev);
+		netif_tx_lock(ndev);
+	}
+
 	u32 temp_mac[2];
 	u32 rcntl = OPT_FRAME_SIZE | 0x04;
 	u32 ecntl = 0x2; /* ETHEREN */
@@ -559,6 +565,12 @@  fec_restart(struct net_device *ndev, int duplex)
 
 	/* Enable interrupts we wish to service */
 	writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
+
+	if (netif_running(ndev)) {
+		napi_enable(&fep->napi);
+		netif_wake_queue(ndev);
+		netif_tx_unlock(ndev);
+	}
 }
 
 static void
@@ -598,8 +610,20 @@  fec_timeout(struct net_device *ndev)
 
 	ndev->stats.tx_errors++;
 
-	fec_restart(ndev, fep->full_duplex);
-	netif_wake_queue(ndev);
+	fep->timeout = 1;
+	schedule_delayed_work(&fep->delay_work, msecs_to_jiffies(1));
+}
+
+static void fec_enet_work(struct work_struct *work)
+{
+	struct fec_enet_private *fep =
+		container_of(work, struct fec_enet_private, delay_work.work);
+
+	if (fep->timeout) {
+		fep->timeout = 0;
+		fec_restart(fep->netdev, fep->full_duplex);
+		netif_wake_queue(fep->netdev);
+	}
 }
 
 static void
@@ -996,9 +1020,6 @@  static void fec_enet_adjust_link(struct net_device *ndev)
 			status_change = 1;
 		}
 
-		/* if any of the above changed restart the FEC */
-		if (status_change)
-			fec_restart(ndev, phy_dev->duplex);
 	} else {
 		if (fep->link) {
 			fec_stop(ndev);
@@ -1010,8 +1031,14 @@  static void fec_enet_adjust_link(struct net_device *ndev)
 spin_unlock:
 	spin_unlock_irqrestore(&fep->hw_lock, flags);
 
-	if (status_change)
+	if (status_change) {
+		/* if any of the above changed restart the FEC,
+		 * fec_restart may sleep. can't call it in spin_lock
+		 */
+		if (phy_dev->link)
+			fec_restart(ndev, phy_dev->duplex);
 		phy_print_status(phy_dev);
+	}
 }
 
 static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
@@ -1882,6 +1909,7 @@  fec_probe(struct platform_device *pdev)
 	if (ret)
 		goto failed_register;
 
+	INIT_DELAYED_WORK(&fep->delay_work, fec_enet_work);
 	return 0;
 
 failed_register:
@@ -1918,6 +1946,7 @@  fec_drv_remove(struct platform_device *pdev)
 	struct resource *r;
 	int i;
 
+	cancel_delayed_work_sync(&fep->delay_work);
 	unregister_netdev(ndev);
 	fec_enet_mii_remove(fep);
 	del_timer_sync(&fep->time_keep);
diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index eb43729..a367b21 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -260,7 +260,8 @@  struct fec_enet_private {
 	int hwts_rx_en;
 	int hwts_tx_en;
 	struct timer_list time_keep;
-
+	struct delayed_work delay_work;
+	int timeout;
 };
 
 void fec_ptp_init(struct net_device *ndev, struct platform_device *pdev);