summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorXu Yang <xu.yang_2@nxp.com>2024-01-29 17:37:38 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-02-19 09:30:41 +0100
commit1c9be13846c0b2abc2480602f8ef421360e1ad9e (patch)
treebcc85d1dcfd8e4e4049ce2d96ef8d21d6a87f957
parent47625b018c6bc788bc10dd654c82696eb0a5ef11 (diff)
usb: roles: fix NULL pointer issue when put module's reference
In current design, usb role class driver will get usb_role_switch parent's module reference after the user get usb_role_switch device and put the reference after the user put the usb_role_switch device. However, the parent device of usb_role_switch may be removed before the user put the usb_role_switch. If so, then, NULL pointer issue will be met when the user put the parent module's reference. This will save the module pointer in structure of usb_role_switch. Then, we don't need to find module by iterating long relations. Fixes: 5c54fcac9a9d ("usb: roles: Take care of driver module reference counting") cc: stable@vger.kernel.org Signed-off-by: Xu Yang <xu.yang_2@nxp.com> Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Link: https://lore.kernel.org/r/20240129093739.2371530-1-xu.yang_2@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/roles/class.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index ae41578bd014..2bad038fb9ad 100644
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -21,6 +21,7 @@ static const struct class role_class = {
struct usb_role_switch {
struct device dev;
struct mutex lock; /* device lock*/
+ struct module *module; /* the module this device depends on */
enum usb_role role;
/* From descriptor */
@@ -135,7 +136,7 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev)
usb_role_switch_match);
if (!IS_ERR_OR_NULL(sw))
- WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
+ WARN_ON(!try_module_get(sw->module));
return sw;
}
@@ -157,7 +158,7 @@ struct usb_role_switch *fwnode_usb_role_switch_get(struct fwnode_handle *fwnode)
sw = fwnode_connection_find_match(fwnode, "usb-role-switch",
NULL, usb_role_switch_match);
if (!IS_ERR_OR_NULL(sw))
- WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
+ WARN_ON(!try_module_get(sw->module));
return sw;
}
@@ -172,7 +173,7 @@ EXPORT_SYMBOL_GPL(fwnode_usb_role_switch_get);
void usb_role_switch_put(struct usb_role_switch *sw)
{
if (!IS_ERR_OR_NULL(sw)) {
- module_put(sw->dev.parent->driver->owner);
+ module_put(sw->module);
put_device(&sw->dev);
}
}
@@ -189,15 +190,18 @@ struct usb_role_switch *
usb_role_switch_find_by_fwnode(const struct fwnode_handle *fwnode)
{
struct device *dev;
+ struct usb_role_switch *sw = NULL;
if (!fwnode)
return NULL;
dev = class_find_device_by_fwnode(&role_class, fwnode);
- if (dev)
- WARN_ON(!try_module_get(dev->parent->driver->owner));
+ if (dev) {
+ sw = to_role_switch(dev);
+ WARN_ON(!try_module_get(sw->module));
+ }
- return dev ? to_role_switch(dev) : NULL;
+ return sw;
}
EXPORT_SYMBOL_GPL(usb_role_switch_find_by_fwnode);
@@ -338,6 +342,7 @@ usb_role_switch_register(struct device *parent,
sw->set = desc->set;
sw->get = desc->get;
+ sw->module = parent->driver->owner;
sw->dev.parent = parent;
sw->dev.fwnode = desc->fwnode;
sw->dev.class = &role_class;