Bluetooth: hci_qca: Fix QCA6390 memdump failure

QCA6390 memdump VSE sometimes come to bluetooth driver
with wrong sequence number as illustrated as follows:
frame # in dec: frame data in hex
1396: ff fd 01 08 74 05 00 37 8f 14
1397: ff fd 01 08 75 05 00 ff bf 38
1414: ff fd 01 08 86 05 00 fb 5e 4b
1399: ff fd 01 08 77 05 00 f3 44 0a
1400: ff fd 01 08 78 05 00 ca f7 41
it is mistook for controller missing packets, so results
in page fault after overwriting memdump buffer allocated.

Fixed by ignoring QCA6390 sequence number check and
checking buffer space before writing.
Signed-off-by: Zijun Hu <zijuhu@codeaurora.org>
Tested-by: Zijun Hu <zijuhu@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/hci_qca.c

@@ -114,6 +114,7 @@ struct qca_memdump_data {
 	char *memdump_buf_tail;
 	u32 current_seq_no;
 	u32 received_dump;
+	u32 ram_dump_size;
 };
 
 struct qca_memdump_event_hdr {
@@ -976,6 +977,8 @@ static void qca_controller_memdump(struct work_struct *work)
 	char nullBuff[QCA_DUMP_PACKET_SIZE] = { 0 };
 	u16 seq_no;
 	u32 dump_size;
+	u32 rx_size;
+	enum qca_btsoc_type soc_type = qca_soc_type(hu);
 
 	while ((skb = skb_dequeue(&qca->rx_memdump_q))) {
 
@@ -1025,10 +1028,12 @@ static void qca_controller_memdump(struct work_struct *work)
 				    dump_size);
 			queue_delayed_work(qca->workqueue,
 					   &qca->ctrl_memdump_timeout,
-					msecs_to_jiffies(MEMDUMP_TIMEOUT_MS));
+					   msecs_to_jiffies(MEMDUMP_TIMEOUT_MS)
+					  );
 
 			skb_pull(skb, sizeof(dump_size));
 			memdump_buf = vmalloc(dump_size);
+			qca_memdump->ram_dump_size = dump_size;
 			qca_memdump->memdump_buf_head = memdump_buf;
 			qca_memdump->memdump_buf_tail = memdump_buf;
 		}
@@ -1051,26 +1056,57 @@ static void qca_controller_memdump(struct work_struct *work)
 		 * the controller. In such cases let us store the dummy
 		 * packets in the buffer.
 		 */
+		/* For QCA6390, controller does not lost packets but
+		 * sequence number field of packat sometimes has error
+		 * bits, so skip this checking for missing packet.
+		 */
 		while ((seq_no > qca_memdump->current_seq_no + 1) &&
-			seq_no != QCA_LAST_SEQUENCE_NUM) {
+		       (soc_type != QCA_QCA6390) &&
+		       seq_no != QCA_LAST_SEQUENCE_NUM) {
 			bt_dev_err(hu->hdev, "QCA controller missed packet:%d",
 				   qca_memdump->current_seq_no);
+			rx_size = qca_memdump->received_dump;
+			rx_size += QCA_DUMP_PACKET_SIZE;
+			if (rx_size > qca_memdump->ram_dump_size) {
+				bt_dev_err(hu->hdev,
+					   "QCA memdump received %d, no space for missed packet",
+					   qca_memdump->received_dump);
+				break;
+			}
 			memcpy(memdump_buf, nullBuff, QCA_DUMP_PACKET_SIZE);
 			memdump_buf = memdump_buf + QCA_DUMP_PACKET_SIZE;
 			qca_memdump->received_dump += QCA_DUMP_PACKET_SIZE;
 			qca_memdump->current_seq_no++;
 		}
 
-		memcpy(memdump_buf, (unsigned char *) skb->data, skb->len);
-		memdump_buf = memdump_buf + skb->len;
-		qca_memdump->memdump_buf_tail = memdump_buf;
-		qca_memdump->current_seq_no = seq_no + 1;
-		qca_memdump->received_dump += skb->len;
+		rx_size = qca_memdump->received_dump + skb->len;
+		if (rx_size <= qca_memdump->ram_dump_size) {
+			if ((seq_no != QCA_LAST_SEQUENCE_NUM) &&
+			    (seq_no != qca_memdump->current_seq_no))
+				bt_dev_err(hu->hdev,
+					   "QCA memdump unexpected packet %d",
+					   seq_no);
+			bt_dev_dbg(hu->hdev,
+				   "QCA memdump packet %d with length %d",
+				   seq_no, skb->len);
+			memcpy(memdump_buf, (unsigned char *)skb->data,
+			       skb->len);
+			memdump_buf = memdump_buf + skb->len;
+			qca_memdump->memdump_buf_tail = memdump_buf;
+			qca_memdump->current_seq_no = seq_no + 1;
+			qca_memdump->received_dump += skb->len;
+		} else {
+			bt_dev_err(hu->hdev,
+				   "QCA memdump received %d, no space for packet %d",
+				   qca_memdump->received_dump, seq_no);
+		}
 		qca->qca_memdump = qca_memdump;
 		kfree_skb(skb);
 		if (seq_no == QCA_LAST_SEQUENCE_NUM) {
-			bt_dev_info(hu->hdev, "QCA writing crash dump of size %d bytes",
-				   qca_memdump->received_dump);
+			bt_dev_info(hu->hdev,
+				    "QCA memdump Done, received %d, total %d",
+				    qca_memdump->received_dump,
+				    qca_memdump->ram_dump_size);
 			memdump_buf = qca_memdump->memdump_buf_head;
 			dev_coredumpv(&hu->serdev->dev, memdump_buf,
 				      qca_memdump->received_dump, GFP_KERNEL);