driver core: Check drivers_autoprobe for all added devices

When a device is hot-plugged, the drivers_autoprobe sysfs attribute is
not checked (at least for PCI devices). This means that
drivers_autoprobe is not working as intended, e.g. hot-plugged PCI
devices will still be autoprobed and bound to drivers even with
drivers_autoprobe disabled.

The problem likely started when device_add() was removed from
pci_bus_add_device() in commit 4f535093cf8f ("PCI: Put pci_dev in device
tree as early as possible") which means that the check for
drivers_autoprobe which used to happen in bus_probe_device() is no
longer present (previously bus_add_device() calls bus_probe_device()).
Conveniently, in commit 91703041697c ("PCI: Allow built-in drivers to
use async initial probing") device_attach() was replaced with
device_initial_probe() which faciliates this change to push the check
for drivers_autoprobe into device_initial_probe().

Make sure all devices check drivers_autoprobe by pushing the
drivers_autoprobe check into device_initial_probe(). This will only
affect devices on the PCI bus for now as device_initial_probe() is only
called by pci_bus_add_device() and bus_probe_device(), but
bus_probe_device() already checks for autoprobe, so callers of
bus_probe_device() should not observe changes on autoprobing.
Note also that pushing this check into device_initial_probe() rather
than device_attach() makes it only affect automatic probing of
drivers (e.g. when a device is hot-plugged), userspace can still choose
to manually bind a driver by writing to drivers_probe sysfs attribute,
even with autoprobe disabled.

Any future callers of device_initial_probe() will respect the
drivers_autoprobe sysfs attribute, which is the intended purpose of
drivers_autoprobe.

Signed-off-by: Vincent Liu <vincent.liu@nutanix.com>
Link: https://patch.msgid.link/20251022120740.2476482-1-vincent.liu@nutanix.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 5e75e1bce5516d2d30884fb3d5fb5a976cc95cbb..320e155c6be77e81ed1efa8f8ecf6f956ab0e3d6 100644 (file)
--- 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 4938a132a085bbe0cbddad2a7b64067057c287e9..349f31bedfa17fa57368d4fae11f074c15bbe08d 100644 (file)
--- 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);
 }
 
 /*