powercap: call put_device() on an error path in powercap_register_control_type()

powercap_register_control_type() calls device_register(), but does not
release the refcount of the device when it fails.

Call put_device() before returning an error to balance the refcount.

Since the kfree(control_type) will be done by powercap_release(), remove
the lines in powercap_register_control_type() before returning the error.

This bug was found by an experimental verifier that I am developing.

Signed-off-by: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
Link: https://patch.msgid.link/20250110010554.1583411-1-joe@pf.is.s.u-tokyo.ac.jp
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c
index 52c32dcbf7d846ac994559f6d111e0d2c287794f..4112a009733826ac2d59de07ad76df85051ffac9 100644 (file)
--- a/drivers/powercap/powercap_sys.c
+++ b/drivers/powercap/powercap_sys.c
@@ -627,8 +627,7 @@ struct powercap_control_type *powercap_register_control_type(
        dev_set_name(&control_type->dev, "%s", name);
        result = device_register(&control_type->dev);
        if (result) {
-               if (control_type->allocated)
-                       kfree(control_type);
+               put_device(&control_type->dev);
                return ERR_PTR(result);
        }
        idr_init(&control_type->idr);