[PATCH] Bluetooth: btintel_pcie: fix TX queue off-by-one

[PATCH] Bluetooth: btintel_pcie: fix TX queue off-by-one

[Pengpeng Hou]

btintel_pcie_send_sync() reads the next transmit slot from
data->ia.tr_hia[] and uses it as an index into the fixed txq descriptor
arrays. The current guard only rejects values strictly greater than
txq->count, so an index equal to the queue depth still falls through and
is used as the next transmit slot one element past the end.

Reject indices at or above the queue depth before preparing the TX
descriptor.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
---
 drivers/bluetooth/btintel_pcie.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 37b744e35bc4..760cb3d1aa18 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -359,7 +359,7 @@ static int btintel_pcie_send_sync(struct btintel_pcie_data *data,
 
 	tfd_index = data->ia.tr_hia[BTINTEL_PCIE_TXQ_NUM];
 
-	if (tfd_index > txq->count)
+	if (tfd_index >= txq->count)
 		return -ERANGE;
 
 	/* Firmware raises alive interrupt on HCI_OP_RESET or
-- 
2.50.1 (Apple Git-155)

RE: Bluetooth: btintel_pcie: fix TX queue off-by-one

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2833 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=1071503

---Test result---

Test Summary:
CheckPatch                    PENDING   0.55 seconds
GitLint                       PENDING   0.33 seconds
SubjectPrefix                 PASS      0.07 seconds
BuildKernel                   PASS      27.28 seconds
CheckAllWarning               PASS      30.18 seconds
CheckSparse                   PASS      29.15 seconds
BuildKernel32                 PASS      26.89 seconds
TestRunnerSetup               PASS      587.68 seconds
TestRunner_l2cap-tester       PASS      28.58 seconds
TestRunner_iso-tester         FAIL      33.90 seconds
TestRunner_bnep-tester        PASS      6.61 seconds
TestRunner_mgmt-tester        FAIL      118.32 seconds
TestRunner_rfcomm-tester      PASS      9.80 seconds
TestRunner_sco-tester         FAIL      14.81 seconds
TestRunner_ioctl-tester       PASS      10.66 seconds
TestRunner_mesh-tester        FAIL      12.61 seconds
TestRunner_smp-tester         PASS      8.91 seconds
TestRunner_userchan-tester    PASS      6.85 seconds
IncrementalBuild              PENDING   0.56 seconds

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

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

##############################
Test: TestRunner_iso-tester - FAIL
Desc: Run iso-tester with test-runner
Output:
BUG: KASAN: slab-use-after-free in le_read_features_complete+0x7e/0x2b0
Total: 141, Passed: 141 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 494, Passed: 489 (99.0%), Failed: 1, Not Run: 4

Failed Test Cases
Read Exp Feature - Success                           Failed       0.113 seconds
##############################
Test: TestRunner_sco-tester - FAIL
Desc: Run sco-tester with test-runner
Output:
WARNING: possible circular locking dependency detected
BUG: sleeping function called from invalid context at net/core/sock.c:3782
Total: 30, Passed: 30 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:
Total: 10, Passed: 8 (80.0%), Failed: 2, Not Run: 0

Failed Test Cases
Mesh - Send cancel - 1                               Timed out    2.569 seconds
Mesh - Send cancel - 2                               Timed out    1.995 seconds
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:



---
Regards,
Linux Bluetooth

Re: [PATCH] Bluetooth: btintel_pcie: fix TX queue off-by-one

[Luiz Augusto von Dentz]

Hi @Kiran K

On Tue, Mar 24, 2026 at 4:51 AM Pengpeng Hou <pengpeng@iscas.ac.cn> wrote:
>
> btintel_pcie_send_sync() reads the next transmit slot from
> data->ia.tr_hia[] and uses it as an index into the fixed txq descriptor
> arrays. The current guard only rejects values strictly greater than
> txq->count, so an index equal to the queue depth still falls through and
> is used as the next transmit slot one element past the end.
>
> Reject indices at or above the queue depth before preparing the TX
> descriptor.
>
> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
> ---
>  drivers/bluetooth/btintel_pcie.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
> index 37b744e35bc4..760cb3d1aa18 100644
> --- a/drivers/bluetooth/btintel_pcie.c
> +++ b/drivers/bluetooth/btintel_pcie.c
> @@ -359,7 +359,7 @@ static int btintel_pcie_send_sync(struct btintel_pcie_data *data,
>
>         tfd_index = data->ia.tr_hia[BTINTEL_PCIE_TXQ_NUM];
>
> -       if (tfd_index > txq->count)
> +       if (tfd_index >= txq->count)
>                 return -ERANGE;
>
>         /* Firmware raises alive interrupt on HCI_OP_RESET or
> --
> 2.50.1 (Apple Git-155)

Looks valid to me, index starts from 0 while count start from 1, so
index == count would probably overflow as well.

-- 
Luiz Augusto von Dentz

RE: [PATCH] Bluetooth: btintel_pcie: fix TX queue off-by-one

[K, Kiran]

Hi Luiz, Pengpeng,

>Subject: Re: [PATCH] Bluetooth: btintel_pcie: fix TX queue off-by-one
>
>Hi @Kiran K
>
>On Tue, Mar 24, 2026 at 4:51 AM Pengpeng Hou <pengpeng@iscas.ac.cn>
>wrote:
>>
>> btintel_pcie_send_sync() reads the next transmit slot from
>> data->ia.tr_hia[] and uses it as an index into the fixed txq
>> data->descriptor
>> arrays. The current guard only rejects values strictly greater than
>> txq->count, so an index equal to the queue depth still falls through
>> txq->and
>> is used as the next transmit slot one element past the end.
>>
>> Reject indices at or above the queue depth before preparing the TX
>> descriptor.
>>
>> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
>> ---
>>  drivers/bluetooth/btintel_pcie.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/bluetooth/btintel_pcie.c
>> b/drivers/bluetooth/btintel_pcie.c
>> index 37b744e35bc4..760cb3d1aa18 100644
>> --- a/drivers/bluetooth/btintel_pcie.c
>> +++ b/drivers/bluetooth/btintel_pcie.c
>> @@ -359,7 +359,7 @@ static int btintel_pcie_send_sync(struct
>> btintel_pcie_data *data,
>>
>>         tfd_index = data->ia.tr_hia[BTINTEL_PCIE_TXQ_NUM];
>>
>> -       if (tfd_index > txq->count)
>> +       if (tfd_index >= txq->count)

Unless the firmware corrupts DMA memory (or there's a serious firmware bug), tfd_index should never reach or exceed txq->count.  With that in mind, the change looks good to me.

>>                 return -ERANGE;
>>
>>         /* Firmware raises alive interrupt on HCI_OP_RESET or
>> --
>> 2.50.1 (Apple Git-155)
>
>Looks valid to me, index starts from 0 while count start from 1, so index == count
>would probably overflow as well.
>
>--
>Luiz Augusto von Dentz

Thanks,
Kiran