[PATCH v1] Bluetooth: btintel_pcie: Fix a potential race condition

[PATCH v1] Bluetooth: btintel_pcie: Fix a potential race condition

[Kiran K]

On HCI_OP_RESET command, firmware raises alive interrupt. Driver needs
to wait for this before sending other command. This patch fixes the potential
miss of alive interrupt due to which HCI_OP_RESET can timeout.

Expected flow:
If tx command is HCI_OP_RESET,
  1. set data->gp0_received = false
  2. send HCI_OP_RESET
  3. wait for alive interrupt

Actual flow having potential race:
If tx command is HCI_OP_RESET,
 1. send HCI_OP_RESET
   1a. Firmware raises alive interrupt here and in ISR
       data->gp0_received  is set to true
 2. set data->gp0_received = false
 3. wait for alive interrupt

Signed-off-by: Kiran K <kiran.k@intel.com>
Fixes: 05c200c8f029 ("Bluetooth: btintel_pcie: Add handshake between driver and firmware")
Reported-by: Bjorn Helgaas <helgaas@kernel.org>
Closes: https://patchwork.kernel.org/project/bluetooth/patch/20241001104451.626964-1-kiran.k@intel.com/
---
 drivers/bluetooth/btintel_pcie.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 63eca52c0e0b..b8b241a92bf9 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -1321,6 +1321,10 @@ static int btintel_pcie_send_frame(struct hci_dev *hdev,
 			if (opcode == 0xfc01)
 				btintel_pcie_inject_cmd_complete(hdev, opcode);
 		}
+		/* Firmware raises alive interrupt on HCI_OP_RESET */
+		if (opcode == HCI_OP_RESET)
+			data->gp0_received = false;
+
 		hdev->stat.cmd_tx++;
 		break;
 	case HCI_ACLDATA_PKT:
@@ -1358,7 +1362,6 @@ static int btintel_pcie_send_frame(struct hci_dev *hdev,
 			   opcode, btintel_pcie_alivectxt_state2str(old_ctxt),
 			   btintel_pcie_alivectxt_state2str(data->alive_intr_ctxt));
 		if (opcode == HCI_OP_RESET) {
-			data->gp0_received = false;
 			ret = wait_event_timeout(data->gp0_wait_q,
 						 data->gp0_received,
 						 msecs_to_jiffies(BTINTEL_DEFAULT_INTR_TIMEOUT_MS));
-- 
2.43.0

RE: [v1] Bluetooth: btintel_pcie: Fix a potential race condition

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2108 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=929500

---Test result---

Test Summary:
CheckPatch                    PENDING   0.24 seconds
GitLint                       PENDING   0.21 seconds
SubjectPrefix                 PASS      0.12 seconds
BuildKernel                   PASS      24.84 seconds
CheckAllWarning               PASS      27.66 seconds
CheckSparse                   PASS      31.43 seconds
BuildKernel32                 PASS      24.99 seconds
TestRunnerSetup               PASS      435.65 seconds
TestRunner_l2cap-tester       PASS      20.58 seconds
TestRunner_iso-tester         PASS      29.82 seconds
TestRunner_bnep-tester        PASS      5.21 seconds
TestRunner_mgmt-tester        FAIL      120.43 seconds
TestRunner_rfcomm-tester      PASS      7.67 seconds
TestRunner_sco-tester         PASS      9.45 seconds
TestRunner_ioctl-tester       PASS      8.22 seconds
TestRunner_mesh-tester        PASS      6.16 seconds
TestRunner_smp-tester         PASS      7.14 seconds
TestRunner_userchan-tester    PASS      5.09 seconds
IncrementalBuild              PENDING   0.47 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: 483 (98.6%), Failed: 3, Not Run: 4

Failed Test Cases
LL Privacy - Add Device 3 (AL is full)               Failed       0.194 seconds
LL Privacy - Set Flags 1 (Add to RL)                 Failed       0.148 seconds
LL Privacy - Set Device Flag 1 (Device Privacy)      Failed       0.148 seconds
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:



---
Regards,
Linux Bluetooth

Re: [PATCH v1] Bluetooth: btintel_pcie: Fix a potential race condition

[patchwork-bot+bluetooth]

Hello:

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

On Fri, 31 Jan 2025 18:30:19 +0530 you wrote:
> On HCI_OP_RESET command, firmware raises alive interrupt. Driver needs
> to wait for this before sending other command. This patch fixes the potential
> miss of alive interrupt due to which HCI_OP_RESET can timeout.
> 
> Expected flow:
> If tx command is HCI_OP_RESET,
>   1. set data->gp0_received = false
>   2. send HCI_OP_RESET
>   3. wait for alive interrupt
> 
> [...]

Here is the summary with links:
  - [v1] Bluetooth: btintel_pcie: Fix a potential race condition
    https://git.kernel.org/bluetooth/bluetooth-next/c/37d0ec8e50ca

You are awesome, thank you!
-- 
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