[PATCH v3] bluetooth: hci_qca: Fix QCA6390 memdump failure

[PATCH v3] bluetooth: hci_qca: Fix QCA6390 memdump failure

[Zijun Hu]

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.

it is fixed by ignoring QCA6390 sequence number error
and checking buffer space before writing.

Signed-off-by: Zijun Hu <zijuhu@codeaurora.org>
---
 drivers/bluetooth/hci_qca.c | 45 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 7 deletions(-)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index e4a6823..f5f4508 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/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))) {
 
@@ -1029,6 +1032,7 @@ static void qca_controller_memdump(struct work_struct *work)
 
 			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;
 		}
@@ -1052,25 +1056,52 @@ static void qca_controller_memdump(struct work_struct *work)
 		 * packets in the buffer.
 		 */
 		while ((seq_no > qca_memdump->current_seq_no + 1) &&
+		       (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);
-- 
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