From: Matt Mackall <mpm@selenic.com>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: netpoll trapped question
Date: Tue, 7 Sep 2004 11:59:42 -0500 [thread overview]
Message-ID: <20040907165942.GY31237@waste.org> (raw)
In-Reply-To: <16701.59261.688607.284454@segfault.boston.redhat.com>
On Tue, Sep 07, 2004 at 12:53:17PM -0400, Jeff Moyer wrote:
> mpm> A random lock private to a given driver, for instance one taken on
> mpm> entry to the IRQ handler. If said driver tries to do a printk inside
> mpm> that lock and we recursively call the handler in netconsole, we're in
> mpm> trouble. These are the issues that will have to be cleaned up in
> mpm> individual drivers. So far, I haven't seen any reports, but I'm pretty
> mpm> sure such cases exist. I suppose it's also possible for us to disable
> mpm> recursion in netconsole instead of at the netpoll level.
>
> Recursion in netconsole is protected by the console semaphore.
Yes, true. But we're still in trouble if we have nic irq handler ->
take private lock -> printk -> netconsole -> nic irq handler -> take
private lock. See?
--
Mathematics is the supreme nostalgia of our time.
next prev parent reply other threads:[~2004-09-07 17:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-08-31 17:10 netpoll trapped question Jeff Moyer
2004-09-06 21:35 ` Matt Mackall
2004-09-07 16:33 ` Jeff Moyer
2004-09-07 16:50 ` Matt Mackall
2004-09-07 16:53 ` Jeff Moyer
2004-09-07 16:59 ` Matt Mackall [this message]
2004-09-07 17:10 ` Jeff Moyer
2004-09-07 17:22 ` Matt Mackall
2004-09-08 8:22 ` Herbert Xu
2004-09-08 8:34 ` Herbert Xu
2004-09-08 11:54 ` Jeff Moyer
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