On Tue, Aug 25, 2015 at 08:33:55AM -0400, Jes Sorensen wrote:
> Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> writes:
> > On Tue, Aug 18, 2015 at 03:14:02PM -0400, Benjamin Romer wrote:
> >> 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 returning an error code when the bus
> >> hasn't been registered.
> >>
> >> Signed-off-by: Benjamin Romer <benjamin.romer@xxxxxxxxxx>
> >> ---
> >> drivers/staging/unisys/visorbus/visorbus_main.c | 3 +++
> >> 1 file changed, 3 insertions(+)
> >>
> >> diff --git a/drivers/staging/unisys/visorbus/visorbus_main.c b/drivers/staging/unisys/visorbus/visorbus_main.c
> >> index 7905ea9..ad2b1ac 100644
> >> --- a/drivers/staging/unisys/visorbus/visorbus_main.c
> >> +++ b/drivers/staging/unisys/visorbus/visorbus_main.c
> >> @@ -863,6 +863,9 @@ int visorbus_register_visor_driver(struct visor_driver *drv)
> >> {
> >> int rc = 0;
> >>
> >> + if (!visorbus_type.p)
> >> + return -ENODEV; /*can't register on a nonexistent bus*/
> >> +
> > IIRC, Greg once told that we should not be working with the internal
> > data structures of struct bus_type.
>
> If you looked at the code you would have noticed this is in fact the bus
> driver, and visorbus_type is defined in this file. I guess we could tell
> visorbus_main.c to not touch visorbus_type by deleting the file
> completely .....
Yes, this is the bus driver, struct bus_type. Maybe the following might
be a better approach where the struct bus_type internals are not touched
yet it will server the purpose.
regards
sudip
diff --git a/drivers/staging/unisys/visorbus/visorbus_main.c b/drivers/staging/unisys/visorbus/visorbus_main.c
index 2309f5f..32500be 100644
--- a/drivers/staging/unisys/visorbus/visorbus_main.c
+++ b/drivers/staging/unisys/visorbus/visorbus_main.c
@@ -31,6 +31,7 @@ static int visorbus_debug;
static int visorbus_forcematch;
static int visorbus_forcenomatch;
static int visorbus_debugref;
+static bool bus_registered;
#define SERIALLOOPBACKCHANADDR (100 * 1024 * 1024)
#define CURRENT_FILE_PC VISOR_BUS_PC_visorbus_main_c
@@ -40,6 +41,7 @@ static int visorbus_debugref;
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);
+static bool is_visorbus_registered(void);
/* BUS type attributes
*
@@ -863,6 +865,9 @@ int visorbus_register_visor_driver(struct visor_driver *drv)
{
int rc = 0;
+ if(!is_visorbus_registered())
+ 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;
@@ -1263,7 +1268,17 @@ create_bus_type(void)
int rc = 0;
rc = bus_register(&visorbus_type);
- return rc;
+
+ if (rc)
+ return rc;
+ bus_registered = true;
+ return 0;
+}
+
+static bool
+is_visorbus_registered(void)
+{
+ return bus_registered;
}
/** Remove the one-and-only one instance of the visor bus type (visorbus_type).
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