diff mbox series

net: bluetooth: fix consistent connection failure caused by the loss of HCI_Connection_Complete event

Message ID 20230823125214.5910-1-by2239112@buaa.edu.cn (mailing list archive)
State Not Applicable
Headers show
Series net: bluetooth: fix consistent connection failure caused by the loss of HCI_Connection_Complete event | expand

Checks

Context Check Description
tedd_an/pre-ci_am fail error: patch failed: net/bluetooth/hci_conn.c:2886 error: net/bluetooth/hci_conn.c: patch does not apply hint: Use 'git am --show-current-patch' to see the failed patch

Commit Message

Xin-Yu Liu Aug. 23, 2023, 12:52 p.m. UTC
During a connection attempt, if the HCI_Connection_Complete event
is lost and not received by the Host, it will result in
a connection failure.

In that process, the hci_conn, the handle of which is still
HCI_CONN_HANDLE_UNSET, will not be removed from the conn_hash
as it would during a regular disconnection opration.
Consequently, when an ACL connection is initiated for the same device,
the hci_conn is found in hash_conn based on "ba", with its state remaining
BT_CONNECT. Then the Host will send an HCI_Create_Connection_Cancel 
command, which will result in subsequent Bluetooth connections 
for the same device consistently failing.

In order to solve the potential bug, if the hci_conn's state is
BT_CONNECT and handle is HCI_CONN_HANDLE_UNSET, remove this hci_conn
from conn_hash. This adjustment could potentially help ensure that the
specific conn is cleaned up at the appropriate times, then the subsequent
connection for the same device will no longer experience failures.

Signed-off-by: Xin-Yu Liu <by2239112@buaa.edu.cn>
---
 net/bluetooth/hci_conn.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

bluez.test.bot@gmail.com Aug. 23, 2023, 1:14 p.m. UTC | #1
This is an automated email and please do not reply to this email.

Dear Submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
While preparing the CI tests, the patches you submitted couldn't be applied to the current HEAD of the repository.

----- Output -----

error: patch failed: net/bluetooth/hci_conn.c:2886
error: net/bluetooth/hci_conn.c: patch does not apply
hint: Use 'git am --show-current-patch' to see the failed patch

Please resolve the issue and submit the patches again.


---
Regards,
Linux Bluetooth
Luiz Augusto von Dentz Aug. 23, 2023, 9:26 p.m. UTC | #2
Hi,

On Wed, Aug 23, 2023 at 5:52 AM Xin-Yu Liu <by2239112@buaa.edu.cn> wrote:
>
> During a connection attempt, if the HCI_Connection_Complete event
> is lost and not received by the Host, it will result in
> a connection failure.
>
> In that process, the hci_conn, the handle of which is still
> HCI_CONN_HANDLE_UNSET, will not be removed from the conn_hash
> as it would during a regular disconnection opration.
> Consequently, when an ACL connection is initiated for the same device,
> the hci_conn is found in hash_conn based on "ba", with its state remaining
> BT_CONNECT. Then the Host will send an HCI_Create_Connection_Cancel
> command, which will result in subsequent Bluetooth connections
> for the same device consistently failing.
>
> In order to solve the potential bug, if the hci_conn's state is
> BT_CONNECT and handle is HCI_CONN_HANDLE_UNSET, remove this hci_conn
> from conn_hash. This adjustment could potentially help ensure that the
> specific conn is cleaned up at the appropriate times, then the subsequent
> connection for the same device will no longer experience failures.
>
> Signed-off-by: Xin-Yu Liu <by2239112@buaa.edu.cn>
> ---
>  net/bluetooth/hci_conn.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
> index 76222565e..219c62579 100644
> --- a/net/bluetooth/hci_conn.c
> +++ b/net/bluetooth/hci_conn.c
> @@ -2886,6 +2886,10 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason)
>                 } else if (conn->type == ACL_LINK) {
>                         if (conn->hdev->hci_ver < BLUETOOTH_VER_1_2)
>                                 break;
> +                       if (conn->state == HCI_CONN_HANDLE_UNSET) {
> +                               hci_conn_cleanup(conn);
> +                               break;
> +                       }

This won't apply upstream if you are wondering why CI hasn't managed
to pick it up, this should be fixed by the following line if
connection cannot be aborted:

https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/tree/net/bluetooth/hci_sync.c?id=c452805643ff9762626f2c87c2640ab7c7099eb8#n5432

>                         r = hci_send_cmd(conn->hdev,
>                                          HCI_OP_CREATE_CONN_CANCEL,
>                                          6, &conn->dst);
> --
> 2.25.1
>
Xin-Yu Liu Aug. 25, 2023, 2:13 p.m. UTC | #3
Hi,

Thanks for your reply!

After receiving your guidance, we implement the code changes you
provided to us and find that the bug has indeed been resolved.

Thank you for your time, support, and for sharing your knowledge.
We look forward to continuing our involvement in the Linux community
and hope to contribute positively, just as you have done.

Best regards,
Xin-Yu Liu

2023/8/24 5:26, Luiz Augusto von Dentz wrote:
> Hi,
>
> On Wed, Aug 23, 2023 at 5:52 AM Xin-Yu Liu <by2239112@buaa.edu.cn> wrote:
>> During a connection attempt, if the HCI_Connection_Complete event
>> is lost and not received by the Host, it will result in
>> a connection failure.
>> In that process, the hci_conn, the handle of which is still
>> HCI_CONN_HANDLE_UNSET, will not be removed from the conn_hash
>> as it would during a regular disconnection opration.
>> Consequently, when an ACL connection is initiated for the same device,
>> the hci_conn is found in hash_conn based on "ba", with its state remaining
>> BT_CONNECT. Then the Host will send an HCI_Create_Connection_Cancel
>> command, which will result in subsequent Bluetooth connections
>> for the same device consistently failing.
>>
>> In order to solve the potential bug, if the hci_conn's state is
>> BT_CONNECT and handle is HCI_CONN_HANDLE_UNSET, remove this hci_conn
>> from conn_hash. This adjustment could potentially help ensure that the
>> specific conn is cleaned up at the appropriate times, then the subsequent
>> connection for the same device will no longer experience failures.
>>
>> Signed-off-by: Xin-Yu Liu <by2239112@buaa.edu.cn>
>> ---
>>   net/bluetooth/hci_conn.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
>> index 76222565e..219c62579 100644
>> --- a/net/bluetooth/hci_conn.c
>> +++ b/net/bluetooth/hci_conn.c
>> @@ -2886,6 +2886,10 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason)
>>                  } else if (conn->type == ACL_LINK) {
>>                          if (conn->hdev->hci_ver < BLUETOOTH_VER_1_2)
>>                                  break;
>> +                       if (conn->state == HCI_CONN_HANDLE_UNSET) {
>> +                               hci_conn_cleanup(conn);
>> +                               break;
>> +                       }
> This won't apply upstream if you are wondering why CI hasn't managed
> to pick it up, this should be fixed by the following line if
> connection cannot be aborted:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/tree/net/bluetooth/hci_sync.c?id=c452805643ff9762626f2c87c2640ab7c7099eb8#n5432
>
>>                          r = hci_send_cmd(conn->hdev,
>>                                           HCI_OP_CREATE_CONN_CANCEL,
>>                                           6, &conn->dst);
>> --
>> 2.25.1
>>
>
diff mbox series

Patch

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 76222565e..219c62579 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -2886,6 +2886,10 @@  int hci_abort_conn(struct hci_conn *conn, u8 reason)
 		} else if (conn->type == ACL_LINK) {
 			if (conn->hdev->hci_ver < BLUETOOTH_VER_1_2)
 				break;
+			if (conn->state == HCI_CONN_HANDLE_UNSET) {
+				hci_conn_cleanup(conn);
+				break;
+			}
 			r = hci_send_cmd(conn->hdev,
 					 HCI_OP_CREATE_CONN_CANCEL,
 					 6, &conn->dst);