[PATCH 1/2] Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()

[PATCH 1/2] Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()

[Douglas Anderson]

The documentation for usb_driver_claim_interface() says that "the
device lock" is needed when the function is called from places other
than probe(). This appears to be the lock for the USB interface
device. The Mediatek btusb code gets called via this path:

  Workqueue: hci0 hci_power_on [bluetooth]
  Call trace:
   usb_driver_claim_interface
   btusb_mtk_claim_iso_intf
   btusb_mtk_setup
   hci_dev_open_sync
   hci_power_on
   process_scheduled_works
   worker_thread
   kthread

With the above call trace the device lock hasn't been claimed. Claim
it.

Without this fix, we'd sometimes see the error "Failed to claim iso
interface". Sometimes we'd even see worse errors, like a NULL pointer
dereference (where `intf->dev.driver` was NULL) with a trace like:

  Call trace:
   usb_suspend_both
   usb_runtime_suspend
   __rpm_callback
   rpm_suspend
   pm_runtime_work
   process_scheduled_works

Both errors appear to be fixed with the proper locking.

Fixes: ceac1cb0259d ("Bluetooth: btusb: mediatek: add ISO data transmission functions")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

 drivers/bluetooth/btusb.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 279fe6c115fa..f69df515d668 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -2638,8 +2638,15 @@ static void btusb_mtk_claim_iso_intf(struct btusb_data *data)
 	struct btmtk_data *btmtk_data = hci_get_priv(data->hdev);
 	int err;
 
+	/*
+	 * The function usb_driver_claim_interface() is documented to need
+	 * locks held if it's not called from a probe routine. The code here
+	 * is called from the hci_power_on workqueue, so grab the lock.
+	 */
+	device_lock(&btmtk_data->isopkt_intf->dev);
 	err = usb_driver_claim_interface(&btusb_driver,
 					 btmtk_data->isopkt_intf, data);
+	device_unlock(&btmtk_data->isopkt_intf->dev);
 	if (err < 0) {
 		btmtk_data->isopkt_intf = NULL;
 		bt_dev_err(data->hdev, "Failed to claim iso interface");
-- 
2.48.0.rc2.279.g1de40edade-goog

[PATCH 2/2] Bluetooth: btusb: mediatek: Add err code to btusb claim iso printout

[Douglas Anderson]

Add the error code to the message "Failed to claim iso
interface". That allows us to know which error case
usb_driver_claim_interface() hit.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

 drivers/bluetooth/btusb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index f69df515d668..df8889e8759b 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -2649,7 +2649,7 @@ static void btusb_mtk_claim_iso_intf(struct btusb_data *data)
 	device_unlock(&btmtk_data->isopkt_intf->dev);
 	if (err < 0) {
 		btmtk_data->isopkt_intf = NULL;
-		bt_dev_err(data->hdev, "Failed to claim iso interface");
+		bt_dev_err(data->hdev, "Failed to claim iso interface: %d", err);
 		return;
 	}
 
-- 
2.48.0.rc2.279.g1de40edade-goog

RE: [1/2] Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2434 bytes --]

This is automated email and please do not reply to this email!

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=925915

---Test result---

Test Summary:
CheckPatch                    PENDING   0.30 seconds
GitLint                       PENDING   0.28 seconds
SubjectPrefix                 PASS      0.12 seconds
BuildKernel                   PASS      24.65 seconds
CheckAllWarning               PASS      26.88 seconds
CheckSparse                   PASS      30.75 seconds
BuildKernel32                 PASS      24.37 seconds
TestRunnerSetup               PASS      432.82 seconds
TestRunner_l2cap-tester       PASS      20.52 seconds
TestRunner_iso-tester         PASS      28.01 seconds
TestRunner_bnep-tester        PASS      4.85 seconds
TestRunner_mgmt-tester        FAIL      123.75 seconds
TestRunner_rfcomm-tester      PASS      7.54 seconds
TestRunner_sco-tester         PASS      9.29 seconds
TestRunner_ioctl-tester       PASS      8.11 seconds
TestRunner_mesh-tester        FAIL      6.27 seconds
TestRunner_smp-tester         PASS      6.96 seconds
TestRunner_userchan-tester    PASS      5.23 seconds
IncrementalBuild              PENDING   0.74 seconds

Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:

##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:

##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 490, Passed: 484 (98.8%), Failed: 2, Not Run: 4

Failed Test Cases
LL Privacy - Add Device 3 (AL is full)               Failed       0.210 seconds
LL Privacy - Set Flags 2 (Enable RL)                 Failed       0.146 seconds
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:
BUG: KASAN: slab-use-after-free in run_timer_softirq+0x76f/0x7d0
WARNING: CPU: 0 PID: 34 at kernel/workqueue.c:2257 __queue_work+0x687/0xb40
Total: 10, Passed: 9 (90.0%), Failed: 1, Not Run: 0

Failed Test Cases
Mesh - Send cancel - 1                               Failed       0.110 seconds
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:



---
Regards,
Linux Bluetooth

Re: [PATCH 1/2] Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()

[patchwork-bot+bluetooth]

Hello:

This series was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Wed, 15 Jan 2025 19:36:36 -0800 you wrote:
> The documentation for usb_driver_claim_interface() says that "the
> device lock" is needed when the function is called from places other
> than probe(). This appears to be the lock for the USB interface
> device. The Mediatek btusb code gets called via this path:
> 
>   Workqueue: hci0 hci_power_on [bluetooth]
>   Call trace:
>    usb_driver_claim_interface
>    btusb_mtk_claim_iso_intf
>    btusb_mtk_setup
>    hci_dev_open_sync
>    hci_power_on
>    process_scheduled_works
>    worker_thread
>    kthread
> 
> [...]

Here is the summary with links:
  - [1/2] Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()
    https://git.kernel.org/bluetooth/bluetooth-next/c/ec5570088c6a
  - [2/2] Bluetooth: btusb: mediatek: Add err code to btusb claim iso printout
    https://git.kernel.org/bluetooth/bluetooth-next/c/6ca1c15fcb92

You are awesome, thank you!
-- 
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