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From: Hillf Danton <hdanton@sina.com>
To: syzbot <syzbot+6cf5652d3df49fae2e3f@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [pm?] KASAN: use-after-free Read in netdev_unregister_kobject
Date: Wed, 24 Apr 2024 05:31:31 +0800
Message-Id: <20240423213131.3040-1-hdanton@sina.com>
In-Reply-To: <000000000000afab690616b12f99@google.com>
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On Mon, 22 Apr 2024 08:35:25 -0700
> syzbot found the following issue on:
> 
> HEAD commit:    3cdb45594619 Merge tag 's390-6.9-4' of git://git.kernel.or..
> git tree:       upstream
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=144067cb180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  3cdb45594619

--- x/net/bluetooth/bnep/core.c
+++ y/net/bluetooth/bnep/core.c
@@ -540,16 +540,6 @@ static int bnep_session(void *arg)
 	return 0;
 }
 
-static struct device *bnep_get_device(struct bnep_session *session)
-{
-	struct l2cap_conn *conn = l2cap_pi(session->sock->sk)->chan->conn;
-
-	if (!conn || !conn->hcon)
-		return NULL;
-
-	return &conn->hcon->dev;
-}
-
 static const struct device_type bnep_type = {
 	.name	= "bluetooth",
 };
@@ -618,7 +608,6 @@ int bnep_add_connection(struct bnep_conn
 	bnep_set_default_proto_filter(s);
 #endif
 
-	SET_NETDEV_DEV(dev, bnep_get_device(s));
 	SET_NETDEV_DEVTYPE(dev, &bnep_type);
 
 	err = register_netdev(dev);
--