ALSA: ac97: fix a double free in snd_ac97_controller_register()

If ac97_add_adapter() fails, put_device() is the correct way to drop
the device reference. kfree() is not required.
Add kfree() if idr_alloc() fails and in ac97_adapter_release() to do
the cleanup.

Found by code review.

Fixes: 74426fbff66e ("ALSA: ac97: add an ac97 bus")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <lihaoxiang@isrc.iscas.ac.cn>
Link: https://patch.msgid.link/20251219162845.657525-1-lihaoxiang@isrc.iscas.ac.cn
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/ac97/bus.c b/sound/ac97/bus.c
index f4254703d29f75e69798b4986b9b2471d858cf7b..bb9b795e02262664810e5d59efe172611b3903c5 100644 (file)
--- a/sound/ac97/bus.c
+++ b/sound/ac97/bus.c
@@ -298,6 +298,7 @@ static void ac97_adapter_release(struct device *dev)
        idr_remove(&ac97_adapter_idr, ac97_ctrl->nr);
        dev_dbg(&ac97_ctrl->adap, "adapter unregistered by %s\n",
                dev_name(ac97_ctrl->parent));
+       kfree(ac97_ctrl);
 }
 
 static const struct device_type ac97_adapter_type = {
@@ -319,7 +320,9 @@ static int ac97_add_adapter(struct ac97_controller *ac97_ctrl)
                ret = device_register(&ac97_ctrl->adap);
                if (ret)
                        put_device(&ac97_ctrl->adap);
-       }
+       } else
+               kfree(ac97_ctrl);
+
        if (!ret) {
                list_add(&ac97_ctrl->controllers, &ac97_controllers);
                dev_dbg(&ac97_ctrl->adap, "adapter registered by %s\n",
@@ -361,14 +364,11 @@ struct ac97_controller *snd_ac97_controller_register(
        ret = ac97_add_adapter(ac97_ctrl);
 
        if (ret)
-               goto err;
+               return ERR_PTR(ret);
        ac97_bus_reset(ac97_ctrl);
        ac97_bus_scan(ac97_ctrl);
 
        return ac97_ctrl;
-err:
-       kfree(ac97_ctrl);
-       return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(snd_ac97_controller_register);