driver: dont update dev_name via device_add path

notice one system /proc/iomem some entries missed the name for pci_devices

it turns that dev->dev.kobj name is changed after device_add.

for pci code: via acpi_pci_root_driver.ops.add (aka acpi_pci_root_add)
==> pci_acpi_scan_root is used to scan pci bus/device, and at the same
time we read the resource for pci_dev in the pci_read_bases, we have
res->name = pci_name(pci_dev); pci_name is calling dev_name.

later via acpi_pci_root_driver.ops.start (aka acpi_pci_root_start) ==>
pci_bus_add_device to add all pci_dev in kobj tree.  pci_bus_add_device
will call device_add.

actually in device_add

        /* first, register with generic layer. */
        error = kobject_add(&dev->kobj, dev->kobj.parent, "%s", dev_name(dev));
        if (error)
                goto Error;

will get one new name for that kobj, old name is freed.

[Impact: fix corrupted names in /proc/iomem ]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 5 insertions, 1 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index d230ff4b3eec..4aa527b8a913 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -891,7 +891,8 @@ int device_add(struct device *dev)
                 set_dev_node(dev, dev_to_node(parent));
 
         /* first, register with generic layer. */
-        error = kobject_add(&dev->kobj, dev->kobj.parent, "%s", dev_name(dev));
+        /* we require the name to be set before, and pass NULL */
+        error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
         if (error)
                 goto Error;
 
diff --git a/lib/kobject.c b/lib/kobject.c
index a6dec32f2ddd..bacf6fe4f7a0 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -218,6 +218,9 @@ int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
         const char *old_name = kobj->name;
         char *s;
 
+        if (kobj->name && !fmt)
+                return 0;
+
         kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
         if (!kobj->name)
                 return -ENOMEM;