netdev - Re: [PATCH v5 1/1 net] net: fec: fix kernel oops when plug/unplug cable many times

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Date:	Tue, 14 May 2013 16:40:32 -0300
From:	Fabio Estevam <festevam@...il.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Shawn Guo <shawn.guo@...aro.org>,
	Frank Li <Frank.Li@...escale.com>, romieu@...zoreil.com,
	r.schwebel@...gutronix.de, davem@...emloft.net,
	l.stach@...gutronix.de, netdev@...r.kernel.org, lznuaa@...il.com
Subject: Re: [PATCH v5 1/1 net] net: fec: fix kernel oops when plug/unplug
 cable many times

Hi Eric,

On Tue, May 14, 2013 at 4:30 PM, Eric Dumazet <eric.dumazet@...il.com> wrote:

> Thats because netif_tx_lock_bh() should be used.

Thanks for your advise.

> And btw, the order of the unlocks should probably be reversed :
>
>               netif_tx_unlock_bh(ndev);
>               netif_wake_queue(ndev);
>               napi_enable(&fep->napi);
>               netif_device_attach(ndev);

I tried the change below and do not see the original warning on mx28:

--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -451,7 +451,7 @@ fec_restart(struct net_device *ndev, int duplex)
                netif_device_detach(ndev);
                napi_disable(&fep->napi);
                netif_stop_queue(ndev);
-               netif_tx_lock(ndev);
+               netif_tx_lock_bh(ndev);
        }

        /* Whack a reset.  We should wait for this. */
@@ -616,10 +616,10 @@ fec_restart(struct net_device *ndev, int duplex)
        writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);

        if (netif_running(ndev)) {
-               netif_device_attach(ndev);
-               napi_enable(&fep->napi);
+               netif_tx_unlock_bh(ndev);
                netif_wake_queue(ndev);
-               netif_tx_unlock(ndev);
+               napi_enable(&fep->napi);
+               netif_device_attach(ndev);
        }
 }

Could someone try it on mx6, please?

If it works I can submit the patch tomorrow.
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