[PATCH 1/2] Bluetooth: hci_conn: fix CIS hold ownership on reuse

[PATCH 1/2] Bluetooth: hci_conn: fix CIS hold ownership on reuse

[Aldo Ariel Panzardo]

Commit 69997d50ec57 ("Bluetooth: ISO: handle bound CIS cleanup via
hci_conn") made hci_bind_cis() and hci_connect_cis() return a
connection with one hold for the ISO layer.  hci_bind_cis() currently
takes that hold only after configuring a CIS, so its BT_CONNECTED and
matching BT_BOUND paths return a bare lookup result.  Its configuration
failure path can likewise call hci_conn_drop() before taking a hold.

Take the hold before any state-dependent return or configuration error
so every successful return follows the documented ownership contract
and every error drop is balanced.

hci_connect_cis() also assumes hci_conn_link() always takes a new CIS
hold before dropping the one returned by hci_bind_cis().  However, the
helper returns an existing link without taking another hold.  In that
case, preserve the CIS hold for the caller and drop the redundant LE
hold because the existing link already owns its parent hold.  Returning
early also avoids changing an existing CIS back to BT_CONNECT.

Fixes: 69997d50ec57 ("Bluetooth: ISO: handle bound CIS cleanup via hci_conn")
Cc: stable@vger.kernel.org
Signed-off-by: Aldo Ariel Panzardo <qwe.aldo@gmail.com>
---
 net/bluetooth/hci_conn.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index b1f911fd4a..827694c3d6 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -2047,6 +2047,8 @@ struct hci_conn *hci_bind_cis(struct hci_dev *hdev, bdaddr_t *dst,
 		cis->conn_timeout = timeout;
 	}
 
+	hci_conn_hold(cis);
+
 	if (cis->state == BT_CONNECTED)
 		return cis;
 
@@ -2088,7 +2090,6 @@ struct hci_conn *hci_bind_cis(struct hci_dev *hdev, bdaddr_t *dst,
 		return ERR_PTR(-EINVAL);
 	}
 
-	hci_conn_hold(cis);
 	cis->state = BT_BOUND;
 
 	return cis;
@@ -2465,6 +2466,12 @@ struct hci_conn *hci_connect_cis(struct hci_dev *hdev, bdaddr_t *dst,
 		return cis;
 	}
 
+	/* The existing link already owns the hold on its parent. */
+	if (cis->link) {
+		hci_conn_drop(le);
+		return cis;
+	}
+
 	link = hci_conn_link(le, cis);
 	hci_conn_drop(cis);
 	if (!link) {
-- 
2.43.0

[PATCH 2/2] Bluetooth: ISO: release unused CIS holds after channel attach

[Aldo Ariel Panzardo]

hci_bind_cis() and hci_connect_cis() return one hci_conn hold for the
ISO layer.  A new channel association consumes that hold, which is
eventually released by iso_conn_free().

There are two cases where iso_chan_add() does not create an association:
it returns success when the socket is already attached to the same
iso_conn, and it returns -EBUSY when another socket is attached.  The
hold returned for the current call is unused in both cases.  This occurs
when deferred setup calls iso_connect_cis() again for its existing
socket, or when another socket attempts to reuse the CIS.

Detect the idempotent case while the connection is locked and release
the unused hold after iso_chan_add().  Also release it on -EBUSY.  Do not
drop it for other errors: a newly allocated iso_conn releases the
transferred hold when its last temporary reference is put.

Fixes: 69997d50ec57 ("Bluetooth: ISO: handle bound CIS cleanup via hci_conn")
Cc: stable@vger.kernel.org
Signed-off-by: Aldo Ariel Panzardo <qwe.aldo@gmail.com>
---
 net/bluetooth/iso.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index a461c8a4ef..329bee9c2e 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -496,6 +496,7 @@ static int iso_connect_cis(struct sock *sk)
 	struct hci_dev  *hdev;
 	bdaddr_t src, dst;
 	u8 src_type;
+	bool already_attached;
 	int err;
 
 	lock_sock(sk);
@@ -568,8 +569,14 @@ static int iso_connect_cis(struct sock *sk)
 		goto unlock;
 	}
 
+	iso_conn_lock(conn);
+	already_attached = iso_pi(sk)->conn == conn && conn->sk == sk;
+	iso_conn_unlock(conn);
+
 	err = iso_chan_add(conn, sk, NULL);
 	iso_conn_put(conn);
+	if (already_attached || err == -EBUSY)
+		hci_conn_drop(hcon);
 	if (err)
 		goto unlock;
 
-- 
2.43.0

Re: [PATCH 1/2] Bluetooth: hci_conn: fix CIS hold ownership on reuse

[patchwork-bot+bluetooth]

Hello:

This series was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Tue, 15 Sep 2026 13:04:29 -0300 you wrote:
> Commit 69997d50ec57 ("Bluetooth: ISO: handle bound CIS cleanup via
> hci_conn") made hci_bind_cis() and hci_connect_cis() return a
> connection with one hold for the ISO layer.  hci_bind_cis() currently
> takes that hold only after configuring a CIS, so its BT_CONNECTED and
> matching BT_BOUND paths return a bare lookup result.  Its configuration
> failure path can likewise call hci_conn_drop() before taking a hold.
> 
> [...]

Here is the summary with links:
  - [1/2] Bluetooth: hci_conn: fix CIS hold ownership on reuse
    https://git.kernel.org/bluetooth/bluetooth-next/c/e06d549fcd4a
  - [2/2] Bluetooth: ISO: release unused CIS holds after channel attach
    https://git.kernel.org/bluetooth/bluetooth-next/c/0fcd4dad555c

You are awesome, thank you!
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