In cases where visorbus is compiled directly into the kernel, if
visorbus registration fails for any reason, it is still possible for
other drivers to call visorbus_register_visor_driver(), which could
cause an oops. Prevent this by saving the result of the call to
create_bus() in a static variable, and return an error code when the bus
hasn't been registered successfully.
Signed-off-by: Benjamin Romer <benjamin.romer@xxxxxxxxxx>
---
drivers/staging/unisys/visorbus/visorbus_main.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/unisys/visorbus/visorbus_main.c b/drivers/staging/unisys/visorbus/visorbus_main.c
index 7905ea9..a272b48 100644
--- a/drivers/staging/unisys/visorbus/visorbus_main.c
+++ b/drivers/staging/unisys/visorbus/visorbus_main.c
@@ -37,6 +37,8 @@ static int visorbus_debugref;
#define POLLJIFFIES_TESTWORK 100
#define POLLJIFFIES_NORMALCHANNEL 10
+static int busreg_rc = -ENODEV; /* stores the result from bus registration */
+
static int visorbus_uevent(struct device *xdev, struct kobj_uevent_env *env);
static int visorbus_match(struct device *xdev, struct device_driver *xdrv);
static void fix_vbus_dev_info(struct visor_device *visordev);
@@ -863,6 +865,9 @@ int visorbus_register_visor_driver(struct visor_driver *drv)
{
int rc = 0;
+ if (busreg_rc < 0)
+ return -ENODEV; /*can't register on a nonexistent bus*/
+
drv->driver.name = drv->name;
drv->driver.bus = &visorbus_type;
drv->driver.probe = visordriver_probe_device;
@@ -1262,10 +1267,8 @@ remove_bus_instance(struct visor_device *dev)
static int
create_bus_type(void)
{
- int rc = 0;
-
- rc = bus_register(&visorbus_type);
- return rc;
+ busreg_rc = bus_register(&visorbus_type);
+ return busreg_rc;
}
/** Remove the one-and-only one instance of the visor bus type (visorbus_type).
--
2.1.4
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