Bluetooth: vhci: Fix race when opening vhci device

Commit Message

Arkadiusz Bokowy Sept. 20, 2023, 3:30 p.m. UTC

When the vhci device is opened in the two-step way, i.e.: open device
then write a vendor packet with requested controller type, the device
shall respond with a vendor packet which includes HCI index of created
interface.

When the virtual HCI is created, the host sends a reset request to the
controller. This request is processed by the vhci_send_frame() function.
However, this request is send by a different thread, so it might happen
that this HCI request will be received before the vendor response is
queued in the read queue. This results in the HCI vendor response and
HCI reset request inversion in the read queue which leads to improper
behavior of btvirt:

> dmesg
[1754256.640122] Bluetooth: MGMT ver 1.22
[1754263.023806] Bluetooth: MGMT ver 1.22
[1754265.043775] Bluetooth: hci1: Opcode 0x c03 failed: -110

In order to synchronize vhci two-step open/setup process with virtual
HCI initialization, this patch adds internal lock when queuing data in
the vhci_send_frame() function.

Signed-off-by: Arkadiusz Bokowy <[e-mail]>
---
 drivers/bluetooth/hci_vhci.c | 3 +++
 net/bluetooth/hci_sync.c     | 4 ++--
 2 files changed, 5 insertions(+), 2 deletions(-)

Comments

[e-mail] Sept. 20, 2023, 4:04 p.m. UTC | #1

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Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=785987

---Test result---

Test Summary:
CheckPatch                    PASS      0.79 seconds
GitLint                       PASS      0.24 seconds
SubjectPrefix                 PASS      0.08 seconds
BuildKernel                   PASS      35.89 seconds
CheckAllWarning               PASS      44.57 seconds
CheckSparse                   PASS      47.86 seconds
CheckSmatch                   PASS      125.39 seconds
BuildKernel32                 PASS      34.96 seconds
TestRunnerSetup               PASS      560.66 seconds
TestRunner_l2cap-tester       PASS      34.67 seconds
TestRunner_iso-tester         PASS      68.10 seconds
TestRunner_bnep-tester        PASS      11.73 seconds
TestRunner_mgmt-tester        PASS      251.17 seconds
TestRunner_rfcomm-tester      PASS      19.18 seconds
TestRunner_sco-tester         PASS      22.19 seconds
TestRunner_ioctl-tester       PASS      21.92 seconds
TestRunner_mesh-tester        PASS      15.76 seconds
TestRunner_smp-tester         PASS      16.69 seconds
TestRunner_userchan-tester    PASS      13.02 seconds
IncrementalBuild              PASS      35.12 seconds



---
Regards,
Linux Bluetooth

Patch

diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
index 40e2b9fa11a2..f3892e9ce800 100644
--- a/drivers/bluetooth/hci_vhci.c
+++ b/drivers/bluetooth/hci_vhci.c
@@ -74,7 +74,10 @@  static int vhci_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 	struct vhci_data *data = hci_get_drvdata(hdev);
 
 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
+
+	mutex_lock(&data->open_mutex);
 	skb_queue_tail(&data->readq, skb);
+	mutex_unlock(&data->open_mutex);
 
 	wake_up_interruptible(&data->read_wait);
 	return 0;
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 3640d73f9595..2a7d432436a2 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -152,7 +152,7 @@  struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen,
 	struct sk_buff *skb;
 	int err = 0;
 
-	bt_dev_dbg(hdev, "Opcode 0x%4x", opcode);
+	bt_dev_dbg(hdev, "Opcode 0x%4.4x", opcode);
 
 	hci_req_init(&req, hdev);
 
@@ -248,7 +248,7 @@  int __hci_cmd_sync_status_sk(struct hci_dev *hdev, u16 opcode, u32 plen,
 	skb = __hci_cmd_sync_sk(hdev, opcode, plen, param, event, timeout, sk);
 	if (IS_ERR(skb)) {
 		if (!event)
-			bt_dev_err(hdev, "Opcode 0x%4x failed: %ld", opcode,
+			bt_dev_err(hdev, "Opcode 0x%4.4x failed: %ld", opcode,
 				   PTR_ERR(skb));
 		return PTR_ERR(skb);
 	}