diff mbox series

[v2] Bluetooth: hci_event: Fix vendor (unknown) opcode status handling

Message ID 20220811120103.47669-1-hdegoede@redhat.com
State New
Headers show
Series [v2] Bluetooth: hci_event: Fix vendor (unknown) opcode status handling | expand

Commit Message

Hans de Goede Aug. 11, 2022, 12:01 p.m. UTC
Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
handle Command Complete") was (presumably) meant to only refactor things
without any functional changes.

But it does have one undesirable side-effect, before *status would always
be set to skb->data[0] and it might be overridden by some of the opcode
specific handling. While now it always set by the opcode specific handlers.
This means that if the opcode is not known *status does not get set any
more at all!

This behavior change has broken bluetooth support for BCM4343A0 HCIs,
the hci_bcm.c code tries to configure UART attached HCIs at a higher
baudraute using vendor specific opcodes. The BCM4343A0 does not
support this and this used to simply fail:

[   25.646442] Bluetooth: hci0: BCM: failed to write clock (-56)
[   25.646481] Bluetooth: hci0: Failed to set baudrate

After which things would continue with the initial baudraute. But now
that hci_cmd_complete_evt() no longer sets status for unknown opcodes
*status is left at 0. This causes the hci_bcm.c code to think the baudraute
has been changed on the HCI side and to also adjust the UART baudrate,
after which communication with the HCI is broken, leading to:

[   28.579042] Bluetooth: hci0: command 0x0c03 tx timeout
[   36.961601] Bluetooth: hci0: BCM: Reset failed (-110)

And non working bluetooth. Fix this by restoring the previous
default "*status = skb->data[0]" handling for unknown opcodes.

Fixes: c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to handle Command Complete")
Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v2:
- Add a comment that byte 0 containing the status is not guaranteed
  by the Bluetooth specification
---
 net/bluetooth/hci_event.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

bluez.test.bot@gmail.com Aug. 11, 2022, 1:33 p.m. UTC | #1
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=666875

---Test result---

Test Summary:
CheckPatch                    FAIL      1.29 seconds
GitLint                       PASS      0.79 seconds
SubjectPrefix                 PASS      0.66 seconds
BuildKernel                   PASS      35.33 seconds
BuildKernel32                 PASS      30.56 seconds
Incremental Build with patchesPASS      43.89 seconds
TestRunner: Setup             PASS      506.66 seconds
TestRunner: l2cap-tester      PASS      17.73 seconds
TestRunner: bnep-tester       PASS      6.90 seconds
TestRunner: mgmt-tester       PASS      106.74 seconds
TestRunner: rfcomm-tester     PASS      10.39 seconds
TestRunner: sco-tester        PASS      10.24 seconds
TestRunner: smp-tester        PASS      10.17 seconds
TestRunner: userchan-tester   PASS      7.09 seconds

Details
##############################
Test: CheckPatch - FAIL - 1.29 seconds
Run checkpatch.pl script with rule in .checkpatch.conf
[v2] Bluetooth: hci_event: Fix vendor (unknown) opcode status handling\ERROR:GIT_COMMIT_ID: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'Commit fatal: unsaf ("ace/src' is owned by someone else)")'
#68: 
Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
handle Command Complete") was (presumably) meant to only refactor things

total: 1 errors, 0 warnings, 0 checks, 26 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

/github/workspace/src/12941385.patch has style problems, please review.

NOTE: Ignored message types: UNKNOWN_COMMIT_ID

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.




---
Regards,
Linux Bluetooth
Hans de Goede Aug. 11, 2022, 10 p.m. UTC | #2
Hi Luiz,

On 8/11/22 22:27, Luiz Augusto von Dentz wrote:
> Hi Hans,
> 
> On Thu, Aug 11, 2022 at 5:01 AM Hans de Goede <hdegoede@redhat.com> wrote:
>>
>> Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
>> handle Command Complete") was (presumably) meant to only refactor things
>> without any functional changes.
>>
>> But it does have one undesirable side-effect, before *status would always
>> be set to skb->data[0] and it might be overridden by some of the opcode
>> specific handling. While now it always set by the opcode specific handlers.
>> This means that if the opcode is not known *status does not get set any
>> more at all!
>>
>> This behavior change has broken bluetooth support for BCM4343A0 HCIs,
>> the hci_bcm.c code tries to configure UART attached HCIs at a higher
>> baudraute using vendor specific opcodes. The BCM4343A0 does not
>> support this and this used to simply fail:
>>
>> [   25.646442] Bluetooth: hci0: BCM: failed to write clock (-56)
>> [   25.646481] Bluetooth: hci0: Failed to set baudrate
>>
>> After which things would continue with the initial baudraute. But now
>> that hci_cmd_complete_evt() no longer sets status for unknown opcodes
>> *status is left at 0. This causes the hci_bcm.c code to think the baudraute
>> has been changed on the HCI side and to also adjust the UART baudrate,
>> after which communication with the HCI is broken, leading to:
>>
>> [   28.579042] Bluetooth: hci0: command 0x0c03 tx timeout
>> [   36.961601] Bluetooth: hci0: BCM: Reset failed (-110)
>>
>> And non working bluetooth. Fix this by restoring the previous
>> default "*status = skb->data[0]" handling for unknown opcodes.
>>
>> Fixes: c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to handle Command Complete")
>> Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>> Changes in v2:
>> - Add a comment that byte 0 containing the status is not guaranteed
>>   by the Bluetooth specification
>> ---
>>  net/bluetooth/hci_event.c | 20 ++++++++++++++++++++
>>  1 file changed, 20 insertions(+)
>>
>> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
>> index af17dfb20e01..eb43afd5549a 100644
>> --- a/net/bluetooth/hci_event.c
>> +++ b/net/bluetooth/hci_event.c
>> @@ -3996,6 +3996,26 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, void *data,
>>                         break;
>>                 }
>>         }
>> +       if (i == ARRAY_SIZE(hci_cc_table)) {
>> +               /* Unknown opcode, assume byte 0 contains the status, so
>> +                * that e.g. __hci_cmd_sync() properly returns errors
>> +                * for vendor specific commands send by HCI drivers.
>> +                *
>> +                * Note that the specification does not specify that
>> +                * byte 0 is the status:
>> +                *
>> +                * BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 4, Part E
>> +                * page 2189:
>> +                *
>> +                * Return_Parameters:
>> +                * Size: Depends on command
>> +                *
>> +                * For now using byte 0 seems to work fine, but in the future
>> +                * this may need to be updated so that drivers using vendor
>> +                * commands can specify their own completion handler.
>> +                */
>> +               *status = skb->data[0];
>> +       }
>>
>>         handle_cmd_cnt_and_timer(hdev, ev->ncmd);
>>
>> --
>> 2.37.1
> 
> Not sure why CI bot didn't respond to the list but this patch was
> already applied yesterday:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/commit/?id=84a0a27ea39a9caed74d80a78666a91a9ea5e12b

Great, thank you.

Regards,

Hans
diff mbox series

Patch

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index af17dfb20e01..eb43afd5549a 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3996,6 +3996,26 @@  static void hci_cmd_complete_evt(struct hci_dev *hdev, void *data,
 			break;
 		}
 	}
+	if (i == ARRAY_SIZE(hci_cc_table)) {
+		/* Unknown opcode, assume byte 0 contains the status, so
+		 * that e.g. __hci_cmd_sync() properly returns errors
+		 * for vendor specific commands send by HCI drivers.
+		 *
+		 * Note that the specification does not specify that
+		 * byte 0 is the status:
+		 *
+		 * BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 4, Part E
+		 * page 2189:
+		 *
+		 * Return_Parameters:
+		 * Size: Depends on command
+		 *
+		 * For now using byte 0 seems to work fine, but in the future
+		 * this may need to be updated so that drivers using vendor
+		 * commands can specify their own completion handler.
+		 */
+		*status = skb->data[0];
+	}
 
 	handle_cmd_cnt_and_timer(hdev, ev->ncmd);