From 1ef115e82cafa219bd8b39891066e8ef0ad4b6da Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Wed, 20 Aug 2025 17:04:00 -0400 Subject: [PATCH] Bluetooth: hci_event: Detect if HCI_EV_NUM_COMP_PKTS is unbalanced [ Upstream commit 15bf2c6391bafb14a3020d06ec0761bce0803463 ] This attempts to detect if HCI_EV_NUM_COMP_PKTS contain an unbalanced (more than currently considered outstanding) number of packets otherwise it could cause the hcon->sent to underflow and loop around breaking the tracking of the outstanding packets pending acknowledgment. Fixes: f42809185896 ("Bluetooth: Simplify num_comp_pkts_evt function") Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin --- net/bluetooth/hci_event.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 7f26c1aab9a06..c6dbb4aebfbc1 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -3811,7 +3811,17 @@ static void hci_num_comp_pkts_evt(struct hci_dev *hdev, struct sk_buff *skb) if (!conn) continue; - conn->sent -= count; + /* Check if there is really enough packets outstanding before + * attempting to decrease the sent counter otherwise it could + * underflow.. + */ + if (conn->sent >= count) { + conn->sent -= count; + } else { + bt_dev_warn(hdev, "hcon %p sent %u < count %u", + conn, conn->sent, count); + conn->sent = 0; + } switch (conn->type) { case ACL_LINK: -- 2.47.3