From: Keir Fraser <keir.fraser@eu.citrix.com>
To: Juergen Gross <juergen.gross@fujitsu-siemens.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [Patch] avoid deadlock during console output
Date: Mon, 09 Mar 2009 08:28:13 +0000 [thread overview]
Message-ID: <C5DA839D.47DC%keir.fraser@eu.citrix.com> (raw)
In-Reply-To: <49B4B4B1.9060505@fujitsu-siemens.com>
On 09/03/2009 06:18, "Juergen Gross" <juergen.gross@fujitsu-siemens.com>
wrote:
> Hmm, do you think your patch is okay?
> tasklet_schedule is taking another lock and uses BUG_ON then...
> I would suggest to modify tasklet_schedule:
I can live with the error patch of BUG_ON() not working in this one case. I
don't think releasing the lock suffices anyway, as we'll just end up in a
recursive loop until the hypervisor stack overflows. The BUG_ON() here is
more for informative code annotation than because it's at all likely to
fire.
It perhaps makes sense to disable the tasklet_schedule() based on a flag set
in console_force_unlock(). That would at least allow NMI-based watchdog to
print if we did ever hit the BUG_ON() deadlock (or any other crash while the
tasklet lock is held).
-- Keir
prev parent reply other threads:[~2009-03-09 8:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-06 8:46 [Patch] avoid deadlock during console output Juergen Gross
2009-03-06 9:11 ` Keir Fraser
2009-03-09 6:18 ` Juergen Gross
2009-03-09 7:45 ` Juergen Gross
2009-03-09 8:28 ` Keir Fraser [this message]
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