linux-kernel - Re: WARNING: at drivers/iommu/dmar.c:484 warn_invalid

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20130814093607.GB4491@8bytes.org>
Date:	Wed, 14 Aug 2013 11:36:12 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	Bjorn Helgaas <bhelgaas@...gle.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"open list:INTEL IOMMU (VT-d)" <iommu@...ts.linux-foundation.org>,
	David Woodhouse <dwmw2@...radead.org>
Subject: Re: WARNING: at drivers/iommu/dmar.c:484 warn_invalid_dmar with
 Intel Motherboard

On Tue, Jul 09, 2013 at 03:31:06PM -0700, Guenter Roeck wrote:
> On Tue, Jul 09, 2013 at 03:05:39PM -0600, Bjorn Helgaas wrote:
> > [+cc Joerg, David, iommu list]
> > 
> > On Tue, Jul 9, 2013 at 2:24 PM, Guenter Roeck <linux@...ck-us.net> wrote:
> > > I started seeing this problem after updating the BIOS trying fix another issue,
> > > though I may have missed it earlier.
> > >
> > > I understand this is a BIOS bug. Would be great if someone can pass this on
> > > to Intel BIOS engineers.
> > 
> > Maybe.  It'd be nice if Linux handled it better, though.
> > 
> If anyone has an idea how to do that, I'll be happy to write a patch.

I doubt that we can do anything meaningful here. The BIOS is broken in a
way so that we can't use the IOMMU in Linux. We can patch away the
WARN_ON and make it a sumple FW_BUG message, but the noise a WARN_ON
makes maybe help getting this issue fixed.

But I may be convinced otherwise, if people think this WARN_ON is not
worth it.


	Joerg


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