linux-kernel - Re: [PATCH v2 01/10] PCI/LUO: Register with Liveupdate Orchestrator

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: <CAF8kJuMXJ+JE=mJCNyz6ETNQ5evMh15VKo2wFreuZ=6Jz0aGWg@mail.gmail.com>
Date: Tue, 30 Sep 2025 16:38:48 -0700
From: Chris Li <chrisl@...nel.org>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Danilo Krummrich <dakr@...nel.org>, Len Brown <lenb@...nel.org>, 
	Pasha Tatashin <pasha.tatashin@...een.com>, linux-kernel@...r.kernel.org, 
	linux-pci@...r.kernel.org, linux-acpi@...r.kernel.org, 
	David Matlack <dmatlack@...gle.com>, Pasha Tatashin <tatashin@...gle.com>, 
	Jason Miu <jasonmiu@...gle.com>, Vipin Sharma <vipinsh@...gle.com>, 
	Saeed Mahameed <saeedm@...dia.com>, Adithya Jayachandran <ajayachandra@...dia.com>, 
	Parav Pandit <parav@...dia.com>, William Tu <witu@...dia.com>, Mike Rapoport <rppt@...nel.org>, 
	Jason Gunthorpe <jgg@...pe.ca>, Leon Romanovsky <leon@...nel.org>
Subject: Re: [PATCH v2 01/10] PCI/LUO: Register with Liveupdate Orchestrator

On Tue, Sep 30, 2025 at 8:31 AM Greg Kroah-Hartman
<gregkh@...uxfoundation.org> wrote:
>
> On Tue, Sep 16, 2025 at 12:45:09AM -0700, Chris Li wrote:
> > Register PCI subsystem with the Liveupdate Orchestrator
> > and provide noop liveupdate callbacks.
> >
> > Signed-off-by: Chris Li <chrisl@...nel.org>
> > ---
> >  MAINTAINERS              |  2 ++
> >  drivers/pci/Makefile     |  1 +
> >  drivers/pci/liveupdate.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 57 insertions(+)
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 91cec3288cc81aea199f730924eee1f5fda1fd72..85749a5da69f88544ccc749e9d723b1b54c0e3b7 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -14014,11 +14014,13 @@ F:  tools/testing/selftests/livepatch/
> >
> >  LIVE UPDATE
> >  M:   Pasha Tatashin <pasha.tatashin@...een.com>
> > +M:   Chris Li <chrisl@...nel.org>
> >  L:   linux-kernel@...r.kernel.org
> >  S:   Maintained
> >  F:   Documentation/ABI/testing/sysfs-kernel-liveupdate
> >  F:   Documentation/admin-guide/liveupdate.rst
> >  F:   drivers/misc/liveupdate/
> > +F:   drivers/pci/liveupdate/
> >  F:   include/linux/liveupdate.h
> >  F:   include/uapi/linux/liveupdate.h
> >  F:   tools/testing/selftests/liveupdate/
> > diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> > index 67647f1880fb8fb0629d680398f5b88d69aac660..aa1bac7aed7d12c641a6b55e56176fb3cdde4c91 100644
> > --- a/drivers/pci/Makefile
> > +++ b/drivers/pci/Makefile
> > @@ -37,6 +37,7 @@ obj-$(CONFIG_PCI_DOE)               += doe.o
> >  obj-$(CONFIG_PCI_DYNAMIC_OF_NODES) += of_property.o
> >  obj-$(CONFIG_PCI_NPEM)               += npem.o
> >  obj-$(CONFIG_PCIE_TPH)               += tph.o
> > +obj-$(CONFIG_LIVEUPDATE)     += liveupdate.o
> >
> >  # Endpoint library must be initialized before its users
> >  obj-$(CONFIG_PCI_ENDPOINT)   += endpoint/
> > diff --git a/drivers/pci/liveupdate.c b/drivers/pci/liveupdate.c
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..86b4f3a2fb44781c6e323ba029db510450556fa9
> > --- /dev/null
> > +++ b/drivers/pci/liveupdate.c
> > @@ -0,0 +1,54 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +/*
> > + * Copyright (c) 2025, Google LLC.
> > + * Chris Li <chrisl@...nel.org>
> > + */
> > +
> > +#define pr_fmt(fmt) "PCI liveupdate: " fmt
> > +
> > +#include <linux/liveupdate.h>
> > +
> > +#define PCI_SUBSYSTEM_NAME "pci"
> > +
> > +static int pci_liveupdate_prepare(void *arg, u64 *data)
> > +{
> > +     pr_info("prepare data[%llx]\n", *data);
> > +     return 0;
> > +}
> > +
> > +static int pci_liveupdate_freeze(void *arg, u64 *data)
> > +{
> > +     pr_info("freeze data[%llx]\n", *data);
> > +     return 0;
> > +}
> > +
> > +static void pci_liveupdate_cancel(void *arg, u64 data)
> > +{
> > +     pr_info("cancel data[%llx]\n", data);
> > +}
> > +
> > +static void pci_liveupdate_finish(void *arg, u64 data)
> > +{
> > +     pr_info("finish data[%llx]\n", data);
> > +}
> > +
> > +struct liveupdate_subsystem pci_liveupdate_ops = {
> > +     .prepare = pci_liveupdate_prepare,
> > +     .freeze = pci_liveupdate_freeze,
> > +     .cancel = pci_liveupdate_cancel,
> > +     .finish = pci_liveupdate_finish,
> > +     .name = PCI_SUBSYSTEM_NAME,
> > +};
> > +
> > +static int __init pci_liveupdate_init(void)
> > +{
> > +     int ret;
> > +
> > +     ret = liveupdate_register_subsystem(&pci_liveupdate_ops);
> > +     if (ret && liveupdate_state_updated())
> > +             panic("PCI liveupdate: Register subsystem failed: %d", ret);
> > +     WARN(ret, "PCI liveupdate: Register subsystem failed %d", ret);
>
> But this didn't fail.
>
> And you just crashed the box if panic-on-warn is enabled, so if some
> test infrastructure builds this first patch, boom.

Sorry that the second WARN should be removed. That is something during
the rebase conflict resolution somehow slipped through the crack.

I will remove the second WARN() there.

Thanks for catching it.

>
> {sigh}
>
> If you are going to do a "dummy" driver, please make it at least work
> and not do anything bad.

I did test it with a real machine and real PCI device, but I did not
have the panic-on-warn.

Again my bad. Sorry about that.

Chris