From: Neil Horman <nhorman@tuxdriver.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Matt Mackall <mpm@selenic.com>,
"David S. Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, Matt Carlson <mcarlson@broadcom.com>
Subject: Re: netpoll + xmit_lock == deadlock
Date: Wed, 29 Jul 2009 21:02:22 -0400 [thread overview]
Message-ID: <20090730010222.GA4169@localhost.localdomain> (raw)
In-Reply-To: <20090729231735.GB14066@gondor.apana.org.au>
On Thu, Jul 30, 2009 at 07:17:35AM +0800, Herbert Xu wrote:
> On Wed, Jul 29, 2009 at 07:15:17PM -0400, Neil Horman wrote:
> >
> > Not quite. I agree private locking in a driver is a pain when you consider
> > netpoll clients, its not the tx/tx recursion you need to worry about though, its
> > shared locking between the tx and rx path that you need to be worried about.
> > We should be protected against deadlock on the _xmit_lock from what we discussed
> > above, but if you take a lock in the driver, then call printk, its possible that
> > you'll go down the ->poll routine path in the driver. If there you try to take
> > the same private lock, the result is then deadlock.
>
> xmit_lock suffers from exactly the same problem in ->poll.
>
Under what conditions do you try to take the xmit_lock from within a drivers
->poll routine? Do you have an example?
Neil
next prev parent reply other threads:[~2009-07-30 1:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-29 7:35 netpoll + xmit_lock == deadlock Herbert Xu
2009-07-29 19:07 ` Matt Mackall
2009-07-29 19:43 ` Neil Horman
2009-07-29 21:48 ` Matt Mackall
2009-07-29 23:15 ` Neil Horman
2009-07-29 23:17 ` Herbert Xu
2009-07-30 1:02 ` Neil Horman [this message]
2009-07-31 1:27 ` Herbert Xu
2009-07-29 22:38 ` Herbert Xu
2009-07-30 1:06 ` Neil Horman
2009-07-31 1:30 ` Herbert Xu
2009-07-31 12:56 ` Neil Horman
2009-07-31 13:02 ` Herbert Xu
2009-07-31 18:09 ` Neil Horman
2009-08-02 20:07 ` David Miller
2009-08-03 12:05 ` Ben Hutchings
2009-08-03 19:15 ` David Miller
2009-08-03 19:59 ` Matt Mackall
2009-08-04 4:19 ` David Miller
2009-08-04 6:48 ` Herbert Xu
2009-08-04 0:15 ` Herbert Xu
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