linux-kernel - Re: [syzbot] [usb?] KASAN: slab-use-after-free Read in hdm

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Message-ID: <tencent_EAF7DD8919014F8F8DD6259B0DA8123DDD07@qq.com>
Date: Tue, 30 Jul 2024 13:40:09 +0800
From: Edward Adam Davis <eadavis@...com>
To: syzbot+916742d5d24f6c254761@...kaller.appspotmail.com
Cc: linux-kernel@...r.kernel.org,
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [usb?] KASAN: slab-use-after-free Read in hdm_disconnect

move the relase dev to the end

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 933069701c1b

diff --git a/drivers/most/most_usb.c b/drivers/most/most_usb.c
index 485d5ca39951..ed3fcba00cae 100644
--- a/drivers/most/most_usb.c
+++ b/drivers/most/most_usb.c
@@ -1118,15 +1118,14 @@ static void hdm_disconnect(struct usb_interface *interface)
 	del_timer_sync(&mdev->link_stat_timer);
 	cancel_work_sync(&mdev->poll_work_obj);
 
-	if (mdev->dci)
-		device_unregister(&mdev->dci->dev);
 	most_deregister_interface(&mdev->iface);
 
 	kfree(mdev->busy_urbs);
 	kfree(mdev->cap);
 	kfree(mdev->conf);
 	kfree(mdev->ep_address);
-	put_device(&mdev->dci->dev);
+	if (mdev->dci)
+		device_unregister(&mdev->dci->dev);
 	put_device(&mdev->dev);
 }