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From: Anton Vorontsov <cbouatmailru@gmail.com>
To: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Cc: netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/2] ucc_geth: Fix deadlock
Date: Fri, 12 Nov 2010 17:09:47 +0300	[thread overview]
Message-ID: <20101112140947.GB28223@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <1289570109-8160-2-git-send-email-Joakim.Tjernlund@transmode.se>

On Fri, Nov 12, 2010 at 02:55:09PM +0100, Joakim Tjernlund wrote:
> This script:
>  while [ 1==1 ] ; do ifconfig eth0 up; usleep 1950000 ;ifconfig eth0 down; dmesg -c ;done
> causes in just a second or two:
> INFO: task ifconfig:572 blocked for more than 120 seconds.
[...]
> The reason appears to be ucc_geth_stop meets adjust_link as the
> PHY reports PHY changes. I belive adjust_link hangs somewhere,
> holding the PHY lock, because ucc_geth_stop disabled the
> controller HW.
> Fix is to stop the PHY before disabling the controller.
> 
> Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>

It's unclear where exactly adjust_link() hangs, but the patch
looks as the right thing overall.

Thanks!

Reviewed-by: Anton Vorontsov <cbouatmailru@gmail.com>

> ---
>  drivers/net/ucc_geth.c |   10 +++++++---
>  1 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
> index 6c254ed..06a5db3 100644
> --- a/drivers/net/ucc_geth.c
> +++ b/drivers/net/ucc_geth.c
> @@ -2050,12 +2050,16 @@ static void ucc_geth_stop(struct ucc_geth_private *ugeth)
>  
>  	ugeth_vdbg("%s: IN", __func__);
>  
> +	/*
> +	 * Tell the kernel the link is down.
> +	 * Must be done before disabling the controller
> +	 * or deadlock may happen.
> +	 */
> +	phy_stop(phydev);
> +
>  	/* Disable the controller */
>  	ugeth_disable(ugeth, COMM_DIR_RX_AND_TX);
>  
> -	/* Tell the kernel the link is down */
> -	phy_stop(phydev);
> -
>  	/* Mask all interrupts */
>  	out_be32(ugeth->uccf->p_uccm, 0x00000000);

  reply	other threads:[~2010-11-12 14:09 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-12 13:55 [PATCH 1/2] ucc_geth: Do not bring the whole IF down when TX failure Joakim Tjernlund
2010-11-12 13:55 ` [PATCH 2/2] ucc_geth: Fix deadlock Joakim Tjernlund
2010-11-12 14:09   ` Anton Vorontsov [this message]
2010-11-12 20:25     ` David Miller
2010-11-14 14:43     ` Joakim Tjernlund
2010-11-12 14:05 ` [PATCH 1/2] ucc_geth: Do not bring the whole IF down when TX failure Anton Vorontsov
2010-11-12 20:24   ` David Miller

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