On 25/01/24 6:39 pm, Borislav Petkov wrote:
On Tue, Nov 28, 2023 at 10:30:35AM -0800, Harshit Mogalapalli wrote:
In edac_device_register_sysfs_main_kobj(), when dev_root is NULL,
Thanks for checking this.
When is dev_root NULL?
A real use case or this is just from code staring?
This is based on static analysis, not real testing.
diff --git a/drivers/edac/edac_device_sysfs.c b/drivers/edac/edac_device_sysfs.c
index 010c26be5846..4cac14cbdb60 100644
--- a/drivers/edac/edac_device_sysfs.c
+++ b/drivers/edac/edac_device_sysfs.c
@@ -253,11 +253,13 @@ int edac_device_register_sysfs_main_kobj(struct edac_device_ctl_info *edac_dev)
/* register */
dev_root = bus_get_dev_root(edac_subsys);
- if (dev_root) {
- err = kobject_init_and_add(&edac_dev->kobj, &ktype_device_ctrl,
- &dev_root->kobj, "%s", edac_dev->name);
What cb4a0bec0bb9 did looks wrong. That if (err) check should be inside
the if (dev_root).
IOW, that function's error checking needs balancing. Something like
this below.
And looking at the other one, it has the same issue...
---
diff --git a/drivers/edac/edac_device_sysfs.c b/drivers/edac/edac_device_sysfs.c
index 237a542e045a..3476ef13e681 100644
--- a/drivers/edac/edac_device_sysfs.c
+++ b/drivers/edac/edac_device_sysfs.c
@@ -228,8 +228,8 @@ static struct kobj_type ktype_device_ctrl = {
*/
int edac_device_register_sysfs_main_kobj(struct edac_device_ctl_info *edac_dev)
{
- struct device *dev_root;
const struct bus_type *edac_subsys;
+ struct device *dev_root;
int err = -ENODEV;
edac_dbg(1, "\n");
@@ -243,26 +243,26 @@ int edac_device_register_sysfs_main_kobj(struct edac_device_ctl_info *edac_dev)
/* Init the devices's kobject */
memset(&edac_dev->kobj, 0, sizeof(struct kobject));
- /* Record which module 'owns' this control structure
- * and bump the ref count of the module
+ /*
+ * Record which module 'owns' this control structure and bump
+ * the ref count of the module
*/
edac_dev->owner = THIS_MODULE;
if (!try_module_get(edac_dev->owner))
goto err_out;
- /* register */
dev_root = bus_get_dev_root(edac_subsys);
- if (dev_root) {
- err = kobject_init_and_add(&edac_dev->kobj, &ktype_device_ctrl,
- &dev_root->kobj, "%s", edac_dev->name);
- put_device(dev_root);
- }
+ if (!dev_root)
+ goto err_module;
+
+ err = kobject_init_and_add(&edac_dev->kobj, &ktype_device_ctrl,
+ &dev_root->kobj, "%s", edac_dev->name);
if (err) {
- edac_dbg(1, "Failed to register '.../edac/%s'\n",
- edac_dev->name);
+ edac_dbg(1, "Failed to register '.../edac/%s'\n", edac_dev->name);
goto err_kobj_reg;
}
+
kobject_uevent(&edac_dev->kobj, KOBJ_ADD);
/* At this point, to 'free' the control struct,
@@ -273,9 +273,11 @@ int edac_device_register_sysfs_main_kobj(struct edac_device_ctl_info *edac_dev)
return 0;
- /* Error exit stack */
err_kobj_reg:
kobject_put(&edac_dev->kobj);
+ put_device(dev_root);
In this diff, put_device(dev_root) is not called on the success path. I
checked couple of other callers of bus_get_dev_root() and they call
put_device(dev_root) after using dev_root. I think we need to have
put_device() on the success path as well.
+
+err_module:
module_put(edac_dev->owner);
An alternate diff could be:
diff --git a/drivers/edac/edac_device_sysfs.c
b/drivers/edac/edac_device_sysfs.c
index 237a542e045a..0c8e66e40af8 100644
--- a/drivers/edac/edac_device_sysfs.c
+++ b/drivers/edac/edac_device_sysfs.c
@@ -275,7 +275,8 @@ int edac_device_register_sysfs_main_kobj(struct
edac_device_ctl_info *edac_dev)
/* Error exit stack */
err_kobj_reg:
- kobject_put(&edac_dev->kobj);
+ if(dev_root)
+ kobject_put(&edac_dev->kobj);
module_put(edac_dev->owner);
err_out:
Thanks,
Harshit
err_out:
