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From: Coiby Xu <coiby.xu@gmail.com>
To: linux-bluetooth@vger.kernel.org
Cc: syzbot+dd768a260f7358adbaf9@syzkaller.appspotmail.com,
	Johan Hedberg <johan.hedberg@gmail.com>,
	Marcel Holtmann <marcel@holtmann.org>,
	syzkaller-bugs@googlegroups.com,
	open list <linux-kernel@vger.kernel.org>,
	"open list:NETWORKING \[GENERAL\]" <netdev@vger.kernel.org>,
	Jakub Kicinski <kuba@kernel.org>,
	linux-kernel-mentees@lists.linuxfoundation.org,
	"David S. Miller" <davem@davemloft.net>
Subject: [Linux-kernel-mentees] [PATCH] Bluetooth: fix "list_add double add" in hci_conn_complete_evt
Date: Sun, 23 Aug 2020 09:00:22 +0800	[thread overview]
Message-ID: <20200823010022.938532-1-coiby.xu@gmail.com> (raw)
In-Reply-To: <000000000000c57f2d05ac4c5b8e@google.com>

When two HCI_EV_CONN_COMPLETE event packets with status=0 of the same
HCI connection are received, device_add would be called twice which
leads to kobject_add being called twice. Thus duplicate
(struct hci_conn *conn)->dev.kobj.entry would be inserted into
(struct hci_conn *conn)->dev.kobj.kset->list.

This issue can be fixed by checking (struct hci_conn *conn)->debugfs.
If it's not NULL, it means the HCI connection has been completed and we
won't duplicate the work as for processing the first
HCI_EV_CONN_COMPLETE event.

Reported-and-tested-by: syzbot+dd768a260f7358adbaf9@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=dd768a260f7358adbaf9
Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
---
 net/bluetooth/hci_event.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 4b7fc430793c..1233739ce760 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2605,6 +2605,11 @@ static void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 	}

 	if (!ev->status) {
+		if (conn->debugfs) {
+			bt_dev_err(hdev, "The connection has been completed");
+			goto unlock;
+		}
+
 		conn->handle = __le16_to_cpu(ev->handle);

 		if (conn->type == ACL_LINK) {
--
2.28.0

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  parent reply	other threads:[~2020-08-23  1:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <000000000000c57f2d05ac4c5b8e@google.com>
2020-08-20  6:07 ` [Linux-kernel-mentees] BUG: corrupted list in kobject_add_internal Coiby Xu
2020-08-20  6:13   ` Dmitry Vyukov via Linux-kernel-mentees
2020-08-22 16:16     ` Coiby Xu
2020-08-23  1:00 ` Coiby Xu [this message]
2020-08-31 16:06   ` [Linux-kernel-mentees] [PATCH] Bluetooth: fix "list_add double add" in hci_conn_complete_evt Marcel Holtmann
2020-09-02 12:31     ` Coiby Xu
2020-11-08 22:55 ` [Linux-kernel-mentees] BUG: corrupted list in kobject_add_internal syzbot
2020-11-11 11:22   ` Dmitry Vyukov via Linux-kernel-mentees

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