Date: Thu, 16 Feb 2012 18:15:34 -0500
From: Dave Jones <davej@redhat.com>
To: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: soft lockup detector & virtualisation
Message-ID: <20120216231533.GA7392@redhat.com>
Mail-Followup-To: Dave Jones <davej@redhat.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 912
Lines: 27

Lately I've noticed quite a few soft lockup bugs being reported.
In many of them, they're coming from inside virtual guests.

Is the softlockup detector fundamentally broken in this situation ?

If the host doesn't schedule the guest for whatever reason,
or the user suspends the VM and resumes it later ?

Here's the most recent example:
https://bugzilla.redhat.com/attachment.cgi?id=563767

In many of these, the code where it's "stuck" isn't anything
special, which is why I think the guest just hasn't had a
timeslice in 185 seconds.

Is there some way we can perhaps detect we're running virtualised,
and disable the detector automatically ?

thoughts ?

	Dave

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/