mcb: remove is_added flag from mcb_device struct

commit 0f28ada1fbf0054557cddcdb93ad17f767105208 upstream.

When calling mcb_bus_add_devices(), both mcb devices and the mcb
bus will attempt to attach a device to a driver because they share
the same bus_type. This causes an issue when trying to cast the
container of the device to mcb_device struct using to_mcb_device(),
leading to a wrong cast when the mcb_bus is added. A crash occurs
when freing the ida resources as the bus numbering of mcb_bus gets
confused with the is_added flag on the mcb_device struct.

The only reason for this cast was to keep an is_added flag on the
mcb_device struct that does not seem necessary. The function
device_attach() handles already bound devices and the mcb subsystem
does nothing special with this is_added flag so remove it completely.

Fixes: 18d288198099 ("mcb: Correctly initialize the bus's device")
Cc: stable <stable@kernel.org>
Signed-off-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Co-developed-by: Jose Javier Rodriguez Barbarin <JoseJavier.Rodriguez@duagon.com>
Signed-off-by: Jose Javier Rodriguez Barbarin <JoseJavier.Rodriguez@duagon.com>
Link: https://lore.kernel.org/r/20230906114901.63174-2-JoseJavier.Rodriguez@duagon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/linux/mcb.h b/include/linux/mcb.h
index b1a0ad9d23b3..8052e5f20630 100644
--- a/include/linux/mcb.h
+++ b/include/linux/mcb.h
@@ -66,7 +66,6 @@ static inline struct mcb_bus *to_mcb_bus(struct device *dev)
 struct mcb_device {
 	struct device dev;
 	struct mcb_bus *bus;
-	bool is_added;
 	struct mcb_driver *driver;
 	u16 id;
 	int inst;