From: Jarek Poplawski <jarkao2@gmail.com>
To: Alan Cox <alan@linux.intel.com>
Cc: jesse.brandeburg@intel.com, netdev@vger.kernel.org
Subject: Re: [RFC PATCH] e100: Fix workqueue race
Date: Fri, 22 Jan 2010 09:07:31 +0000 [thread overview]
Message-ID: <20100122090731.GC6200@ff.dom.local> (raw)
In-Reply-To: <20100122084200.GB6200@ff.dom.local>
On Fri, Jan 22, 2010 at 08:42:00AM +0000, Jarek Poplawski wrote:
> On 21-01-2010 17:48, Alan Cox wrote:
> > (Incidentally this doesn't seem to be the only net driver that looks
> > suspect here)
> >
> > e100: Fix the TX workqueue race
> >
> > From: Alan Cox <alan@linux.intel.com>
> >
> > Nothing stops the workqueue being left to run in parallel with close or a
> > few other operations. This causes double unmaps and the like.
> >
> > See kerneloops.org #1041230 for an example
> >
> > Signed-off-by: Alan Cox <alan@linux.intel.com>
> > ---
> >
> > drivers/net/e100.c | 13 +++++++++++--
> > 1 files changed, 11 insertions(+), 2 deletions(-)
> >
> >
> > diff --git a/drivers/net/e100.c b/drivers/net/e100.c
> > index 5c7a155..5e02e4f 100644
> > --- a/drivers/net/e100.c
> > +++ b/drivers/net/e100.c
> > @@ -2232,7 +2232,7 @@ err_rx_clean_list:
> > return err;
> > }
> >
> > -static void e100_down(struct nic *nic)
> > +static void e100_do_down(struct nic *nic)
> > {
> > /* wait here for poll to complete */
> > napi_disable(&nic->napi);
> > @@ -2245,6 +2245,15 @@ static void e100_down(struct nic *nic)
> > e100_rx_clean_list(nic);
> > }
> >
> > +/* For the non TX timeout case we want to kill the tx timeout before
> > + we do this otherwise a parallel tx timeout will make a nasty mess. */
> > +
> > +static void e100_down(struct nic *nic)
> > +{
> > + cancel_work_sync(&nic->tx_timeout_task);
>
> Can't tx_timeout_task be triggered just between these two calls here?
More exactly: except when this is called from dev_close(), where it
should work OK. (At least until tx_timeout_task doesn't take any lock
held here - especially rtnl_lock.)
Jarek P.
>
> > + e100_do_down(nic);
> > +}
> > +
> > static void e100_tx_timeout(struct net_device *netdev)
> > {
> > struct nic *nic = netdev_priv(netdev);
> > @@ -2261,7 +2270,7 @@ static void e100_tx_timeout_task(struct work_struct *work)
> >
> > DPRINTK(TX_ERR, DEBUG, "scb.status=0x%02X\n",
> > ioread8(&nic->csr->scb.status));
> > - e100_down(netdev_priv(netdev));
> > + e100_do_down(netdev_priv(netdev));
> > e100_up(netdev_priv(netdev));
> > }
> >
> > --
next prev parent reply other threads:[~2010-01-22 9:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-21 16:48 [RFC PATCH] e100: Fix workqueue race Alan Cox
2010-01-21 17:20 ` Stephen Hemminger
2010-01-22 8:42 ` Jarek Poplawski
2010-01-22 9:07 ` Jarek Poplawski [this message]
2010-01-22 9:38 ` Jarek Poplawski
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