linux-kernel - Re: [PATCH 0/4] PCI: Add support and tests for FIXUP quirks in modules

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

Message-ID: <aMhd4REssOE-AlYw@google.com>
Date: Mon, 15 Sep 2025 11:41:37 -0700
From: Brian Norris <briannorris@...omium.org>
To: Christoph Hellwig <hch@...radead.org>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
	Luis Chamberlain <mcgrof@...nel.org>,
	Petr Pavlu <petr.pavlu@...e.com>,
	Daniel Gomez <da.gomez@...nel.org>, linux-pci@...r.kernel.org,
	David Gow <davidgow@...gle.com>, Rae Moar <rmoar@...gle.com>,
	linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-modules@...r.kernel.org,
	Johannes Berg <johannes@...solutions.net>,
	Sami Tolvanen <samitolvanen@...gle.com>,
	Richard Weinberger <richard@....at>, Wei Liu <wei.liu@...nel.org>,
	Brendan Higgins <brendan.higgins@...ux.dev>,
	kunit-dev@...glegroups.com,
	Anton Ivanov <anton.ivanov@...bridgegreys.com>,
	linux-um@...ts.infradead.org
Subject: Re: [PATCH 0/4] PCI: Add support and tests for FIXUP quirks in
 modules

Hi Christoph,

On Mon, Sep 15, 2025 at 06:48:22AM -0700, Christoph Hellwig wrote:
> On Fri, Sep 12, 2025 at 03:59:31PM -0700, Brian Norris wrote:
> > This series primarily adds support for DECLARE_PCI_FIXUP_*() in modules.
> > There are a few drivers that already use this, and so they are
> > presumably broken when built as modules.
> 
> That's a reall bad idea, because it allows random code to insert quirks
> not even bound to the hardware they support.

I see fixups in controller drivers here:

drivers/pci/controller/dwc/pci-imx6.c
drivers/pci/controller/dwc/pci-keystone.c
drivers/pci/controller/dwc/pcie-qcom.c
drivers/pci/controller/pci-loongson.c
drivers/pci/controller/pci-tegra.c
drivers/pci/controller/pcie-iproc-bcma.c
drivers/pci/controller/pcie-iproc.c

Are any of those somehow wrong?

And if they are not wrong, then is this a good reason to disallow making
these drivers modular? (Yes, few of them are currently modular; but I
don't see why that *must* be the case.)

I agree, as with many kernel features, there are plenty of ways to use
them incorrectly. But I'm just trying to patch over one rough edge about
how to use them incorrectly, and I don't really see why it's such a bad
idea.

> So no, modules should not allow quirks, but the kernel should probably
> be nice enough to fail compilation when someone is attemping that
> instead of silently ignoring the quirks.

Sure, if consensus says we should not support this, I'd definitely like
to make this failure mode more obvious -- likely a build error.

Thanks for your thoughts,
Brian