From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Tim Sander <tim01@vlsi.informatik.tu-darmstadt.de>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Sascha Hauer <s.hauer@pengutronix.de>,
Greg Ungerer <gerg@uclinux.org>,
netdev@vger.kernel.org
Subject: Re: Latest PreemptRT patch error on imx35
Date: Mon, 31 Aug 2009 15:22:00 +0200 [thread overview]
Message-ID: <20090831132200.GA21836@pengutronix.de> (raw)
In-Reply-To: <200908311143.08952.tim01@vlsi.informatik.tu-darmstadt.de>
Hello Tim,
> I just bootet 2.6.31-rc8-rt9 on the phycore-imx35 development board,
> without any additional patches. The FEC Ethernet Controller went belly
> up, but the system booted nevertheless. [...]
The problem is that &fep->mii_lock is taken twice. On a normal (i.e.
non-RT) UP system that doesn't hurt because spinlocks are noops (unless
you have some debugging code activated).
The exact problem is:
fec_enet_mii (this takes &fep->mii_lock) and calls mip->mii_func
which happens to be mii_queue. mii_queue in turn takes
&fep->mii_lock again.
The correct fix is probably to split mii_queue into a function that
locks and a function that does the actual work. And then use the latter
in fec_enet_mii.
I'd prepare a patch but my wife just called me to eat some cake :-)
So maybe later today or tomorrow, we'll see.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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next parent reply other threads:[~2009-08-31 13:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200908311143.08952.tim01@vlsi.informatik.tu-darmstadt.de>
2009-08-31 13:22 ` Uwe Kleine-König [this message]
2009-08-31 15:29 ` Latest PreemptRT patch error on imx35 Tim Sander
2009-08-31 16:37 ` [PATCH] " Tim Sander
2009-09-02 9:14 ` [PATCH 1/2] fec: fix recursive locking of mii_lock Uwe Kleine-König
2009-09-02 9:14 ` [PATCH 2/2] fec: don't enable irqs in hard irq context Uwe Kleine-König
2009-09-03 1:14 ` Greg Ungerer
2009-09-03 6:17 ` David Miller
2009-09-03 1:16 ` [PATCH 1/2] fec: fix recursive locking of mii_lock Greg Ungerer
2009-09-03 6:17 ` David Miller
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