linux-kernel - [PATCH 1/1] Bluetooth: make the balance of judgement condition to fix a false report

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Date:   Thu, 8 Nov 2018 13:47:45 +0800
From:   Zumeng Chen <zumeng.chen@...il.com>
To:     <linux-bluetooth@...r.kernel.org>
CC:     <marcel@...tmann.org>, <johan.hedberg@...il.com>,
        <linux-kernel@...r.kernel.org>, Zumeng Chen <zumeng.chen@...il.com>
Subject: [PATCH 1/1] Bluetooth: make the balance of judgement condition to fix a false report

This patch is to balance the condition scope between hci_get_cmd_complete and
hci_event_packet about orig_skb as follows: 

        if (req_complete_skb || event == HCI_EV_CMD_STATUS ||
            event == HCI_EV_CMD_COMPLETE)
                orig_skb = skb_clone(skb, GFP_KERNEL);

And hci_get_cmd_complete will bt_dev_err out when HCI_EV_CMD_STATUS, so a lot
of asymmetric conditions are triggered. Since both of them are the entry into
hci_get_cmd_complete, we'd better get STATUS into judge the false out there.

Signed-off-by: Zumeng Chen <zumeng.chen@...il.com>
---

Hi expert,

This issue existed whether or not T_DBG had been changed into bt_dev_err, which
just shows the issue explicitly. I noticed actually that opcode doesn't match
ev->opcode either at the same time. And there might be some logic issue about
HCI_EV_CMD_COMPLETE between protocol and drivers. I'm not familar with the whole
bluetooth protocol, and not gonna to dig more, so all yours guys~

Cheers,
Zumeng

 net/bluetooth/hci_event.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 235b5aa..d848663 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5217,7 +5217,8 @@ static bool hci_get_cmd_complete(struct hci_dev *hdev, u16 opcode,
 		return true;
 	}

-	if (hdr->evt != HCI_EV_CMD_COMPLETE) {
+	if (!((hdr->evt == HCI_EV_CMD_COMPLETE) ||
+		(hdr->evt == HCI_EV_CMD_STATUS))) {
 		bt_dev_err(hdev, "last event is not cmd complete (0x%2.2x)",
 			   hdr->evt);
 		return false;
-- 
2.7.4