Received-SPF: pass (google.com: best guess record for domain of linux-bluetooth-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Alain Michaud <alainm@chromium.org>
To:     linux-bluetooth@vger.kernel.org
Cc:     Alain Michaud <alainm@chromium.org>
Subject: [PATCH v1] bluetooth: guard against controllers sending zero'd events
Date:   Fri, 28 Feb 2020 20:51:46 +0000
Message-Id: <20200228205146.161229-1-alainm@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-bluetooth-owner@vger.kernel.org
Precedence: bulk

Some controllers have been observed to send zero'd events under some
conditions.  This change guards against this condition as well as adding
a trace to facilitate diagnosability of this condition.

Signed-off-by: Alain Michaud <alainm@chromium.org>
---

 net/bluetooth/hci_event.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 591e7477e925..f865eddb8d69 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5868,7 +5868,8 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 	u8 status = 0, event = hdr->evt, req_evt = 0;
 	u16 opcode = HCI_OP_NOP;
 
-	if (hdev->sent_cmd && bt_cb(hdev->sent_cmd)->hci.req_event == event) {
+	if (hdev->sent_cmd && event &&
+	    bt_cb(hdev->sent_cmd)->hci.req_event == event) {
 		struct hci_command_hdr *cmd_hdr = (void *) hdev->sent_cmd->data;
 		opcode = __le16_to_cpu(cmd_hdr->opcode);
 		hci_req_cmd_complete(hdev, opcode, status, &req_complete,
@@ -5876,6 +5877,9 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 		req_evt = event;
 	}
 
+	if (!event)
+		BT_ERR("Received unexpected HCI Event 00000000");
+
 	/* If it looks like we might end up having to call
 	 * req_complete_skb, store a pristine copy of the skb since the
 	 * various handlers may modify the original one through
-- 
2.25.0.265.gbab2e86ba0-goog