linux-kernel - Re: [PATCH] PCI: Check drivers_autoprobe for all added devices

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Message-ID: <2025100209-hefty-catalyst-e5b2@gregkh>
Date: Thu, 2 Oct 2025 07:55:57 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Vincent Liu <vincent.liu@...anix.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
	Danilo Krummrich <dakr@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PCI: Check drivers_autoprobe for all added devices

On Wed, Oct 01, 2025 at 04:15:07PM +0100, Vincent Liu wrote:
> When a PCIe device is hot-plugged, or when a VF is created, the
> drivers_autoprobe sysfs attribute is not checked. This means that
> drivers_autoprobe is not working as intended, e.g. hot-plugged devices
> will still be autoprobed and bound to drivers even with
> drivers_autoprobe disabled.
> 
> Make sure all devices check drivers_autoprobe by pushing the
> drivers_autoprobe check into device_initial_probe. This should only
> affect devices on the PCI bus as device_initial_probe is only called by
> pci_bus_add_device (bus_probe_device already checks for autoprobe).
> In particular, only hot-plugged PCIe devices/VFs should be affected as
> the default value of pci/drivers_autoprobe remains 1 and can only be
> cleared from userland.
> 
> Signed-off-by: Vincent Liu <vincent.liu@...anix.com>
> ---
>  drivers/base/bus.c |  3 +--
>  drivers/base/dd.c  | 10 +++++++++-
>  2 files changed, 10 insertions(+), 3 deletions(-)

If this is a PCI-specific issue, why not cc: the pci developers and
maintainer as well?

Also, a PCI patch shouldn't be for the driver-core only, I think the
subject line needs to have "driver core" in it.

> 
> diff --git a/drivers/base/bus.c b/drivers/base/bus.c
> index 5e75e1bce551..320e155c6be7 100644
> --- a/drivers/base/bus.c
> +++ b/drivers/base/bus.c
> @@ -533,8 +533,7 @@ void bus_probe_device(struct device *dev)
>  	if (!sp)
>  		return;
>  
> -	if (sp->drivers_autoprobe)
> -		device_initial_probe(dev);
> +	device_initial_probe(dev);
>  
>  	mutex_lock(&sp->mutex);
>  	list_for_each_entry(sif, &sp->interfaces, node)
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 13ab98e033ea..37fc57e44e54 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -1077,7 +1077,15 @@ EXPORT_SYMBOL_GPL(device_attach);
>  
>  void device_initial_probe(struct device *dev)
>  {
> -	__device_attach(dev, true);
> +	struct subsys_private *sp = bus_to_subsys(dev->bus);
> +
> +	if (!sp)
> +		return;
> +
> +	if (sp->drivers_autoprobe)
> +		__device_attach(dev, true);
> +
> +	subsys_put(sp);
>  }


I don't see why this is specific to PCI VF devices.  Did you see the
recent PCI patch for not probing VF devices that was sent out yesterday?
I think that might fix this instead:
	https://lore.kernel.org/r/20251002020010.315944-1-jhubbard@nvidia.com

thanks,

greg k-h