From: Matt Mackall <mpm@selenic.com>
To: Andi Kleen <ak@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>,
Andrew Morton <akpm@osdl.org>,
colin@colino.net, netdev@oss.sgi.com
Subject: Re: [PATCH] Prevent netpoll hanging when link is down
Date: Mon, 11 Oct 2004 11:22:24 -0500 [thread overview]
Message-ID: <20041011162224.GL31237@waste.org> (raw)
In-Reply-To: <20041011154000.GB26350@wotan.suse.de>
On Mon, Oct 11, 2004 at 05:40:00PM +0200, Andi Kleen wrote:
> On Sun, Oct 10, 2004 at 08:59:28PM -0700, David S. Miller wrote:
> >
> > Wait, I think I see the problem.
> >
> > Sungem processes link status in it's ->poll() NAPI handler.
> > This occurs via calls to gem_pcs_interrupt(), for example.
> > Non-pcs sungem variants use a timer to poll link status.
> >
> > When the link changes state, this link state processing
> > does printk()'s.
> >
> > So perhaps that is why it deadlocks.
>
> printk handles recursion with the down_trylock on console_sem.
> So it shouldn't deadlock.
If we're in the ->poll() handler for non-netpoll reasons, and the link
state changes, causing a printk, we'll potentially reenter ->poll() via
netconsole.
This also explains the original fix quite nicely. Colin, can you try
commenting out all the printks in gem_pcs_interrupt and if that works,
we'll start thinking about a proper fix.
--
Mathematics is the supreme nostalgia of our time.
next prev parent reply other threads:[~2004-10-11 16:22 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20041006232544.53615761@jack.colino.net>
2004-10-06 21:43 ` [PATCH] Prevent netpoll hanging when link is down Matt Mackall
2004-10-07 5:53 ` Colin Leroy
2004-10-07 6:49 ` David S. Miller
2004-10-07 8:33 ` Colin Leroy
2004-10-07 8:45 ` Colin Leroy
2004-10-07 14:05 ` Colin Leroy
2004-10-07 18:28 ` David S. Miller
2004-10-07 18:41 ` Matt Mackall
2004-10-07 20:00 ` Colin Leroy
2004-10-07 18:43 ` Andi Kleen
2004-10-07 20:44 ` Colin Leroy
2004-10-07 21:45 ` Andi Kleen
2004-10-07 21:50 ` Matt Mackall
2004-10-07 22:07 ` David S. Miller
2004-10-07 23:43 ` Matt Mackall
2004-10-07 23:50 ` Andi Kleen
2004-10-08 6:46 ` Colin Leroy
2004-10-08 21:53 ` Matt Mackall
2004-10-08 7:06 ` Colin Leroy
2004-10-08 22:00 ` Matt Mackall
2004-10-08 22:18 ` Andrew Morton
2004-10-11 3:59 ` David S. Miller
2004-10-11 15:40 ` Andi Kleen
2004-10-11 16:22 ` Matt Mackall [this message]
2004-10-11 16:32 ` Andi Kleen
2004-10-11 16:36 ` Matt Mackall
2004-10-11 16:43 ` Andi Kleen
2004-10-11 16:58 ` Matt Mackall
2004-10-11 17:41 ` Andi Kleen
2004-10-11 20:45 ` Colin Leroy
[not found] ` <5cac192f0410181443303379e2@mail.gmail.com>
[not found] ` <5cac192f041018145824acce5a@mail.gmail.com>
[not found] ` <20041020161119.6e30efe5@pirandello>
[not found] ` <5cac192f0410200848179ccc81@mail.gmail.com>
2004-10-21 16:36 ` Colin Leroy
2004-10-24 15:22 ` Eric Lemoine
2004-10-07 22:08 ` David S. Miller
2004-10-08 6:54 ` Colin Leroy
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