[PATCH net v2 1/4] dpll: fix pin dump crash after module unbind

Disallow dump of unregistered parent pins, it is possible when parent
pin and dpll device registerer kernel module instance unbinds, and
other kernel module instances of the same dpll device have pins
registered with the parent pin. The user can invoke a pin-dump but as
the parent was unregistered, those shall not be accessed by the
userspace, prevent that by checking if parent pin is still registered.

Fixes: 9d71b54b65b1 ("dpll: netlink: Add DPLL framework base functions")
Reviewed-by: Jan Glaza <redacted>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
---
 drivers/dpll/dpll_netlink.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index ce7cf736f020..b53478374a38 100644
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c

@@ -328,6 +328,8 @@ dpll_msg_add_pin_parents(struct sk_buff *msg, struct dpll_pin *pin,
 		void *parent_priv;
 
 		ppin = ref->pin;
+		if (!xa_get_mark(&dpll_pin_xa, ppin->id, DPLL_REGISTERED))
+			continue;
 		parent_priv = dpll_pin_on_dpll_priv(dpll_ref->dpll, ppin);
 		ret = ops->state_on_pin_get(pin,
 					    dpll_pin_on_pin_priv(ppin, pin),

-- 
2.38.1