Bluetooth: Free potentially unfreed SCO connection

Commit Message

Archie Pusaka Feb. 3, 2023, 9:30 a.m. UTC

From: Archie Pusaka <[e-mail]>

It is possible to initiate a SCO connection while deleting the
corresponding ACL connection, e.g. in below scenario:

(1) < hci setup sync connect command
(2) > hci disconn complete event (for the acl connection)
(3) > hci command complete event (for(1), failure)

When it happens, hci_cs_setup_sync_conn won't be able to obtain the
reference to the SCO connection, so it will be stuck and potentially
hinder subsequent connections to the same device.

This patch prevents that by also deleting the SCO connection if it is
still not established when the corresponding ACL connection is deleted.

Signed-off-by: Archie Pusaka <[e-mail]>
Reviewed-by: Ying Hsu <[e-mail]>

---

 net/bluetooth/hci_conn.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Comments

[e-mail] Feb. 3, 2023, 9:57 a.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=718492

---Test result---

Test Summary:
CheckPatch                    PASS      1.04 seconds
GitLint                       PASS      0.34 seconds
SubjectPrefix                 PASS      0.11 seconds
BuildKernel                   PASS      32.67 seconds
CheckAllWarning               PASS      35.09 seconds
CheckSparse                   PASS      40.33 seconds
CheckSmatch                   PASS      108.31 seconds
BuildKernel32                 PASS      31.15 seconds
TestRunnerSetup               PASS      446.14 seconds
TestRunner_l2cap-tester       PASS      16.98 seconds
TestRunner_iso-tester         PASS      17.80 seconds
TestRunner_bnep-tester        PASS      5.76 seconds
TestRunner_mgmt-tester        PASS      114.33 seconds
TestRunner_rfcomm-tester      PASS      9.19 seconds
TestRunner_sco-tester         PASS      8.51 seconds
TestRunner_ioctl-tester       PASS      10.02 seconds
TestRunner_mesh-tester        PASS      7.42 seconds
TestRunner_smp-tester         PASS      8.30 seconds
TestRunner_userchan-tester    PASS      6.05 seconds
IncrementalBuild              PASS      28.98 seconds



---
Regards,
Linux Bluetooth

[e-mail] Feb. 3, 2023, 8:30 p.m. UTC | #2

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <[e-mail]>:

On Fri,  3 Feb 2023 17:30:55 +0800 you wrote:
> From: Archie Pusaka <[e-mail]>
> 
> It is possible to initiate a SCO connection while deleting the
> corresponding ACL connection, e.g. in below scenario:
> 
> (1) < hci setup sync connect command
> (2) > hci disconn complete event (for the acl connection)
> (3) > hci command complete event (for(1), failure)
> 
> [...]

Here is the summary with links:
  - Bluetooth: Free potentially unfreed SCO connection
    https://git.kernel.org/bluetooth/bluetooth-next/c/c2c762af5650

You are awesome, thank you!

Patch

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 61a34801e61e..838f51c272a6 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -1061,8 +1061,15 @@  int hci_conn_del(struct hci_conn *conn)
 
 	if (conn->type == ACL_LINK) {
 		struct hci_conn *sco = conn->link;
-		if (sco)
+		if (sco) {
 			sco->link = NULL;
+			/* Due to race, SCO connection might be not established
+			 * yet at this point. Delete it now, otherwise it is
+			 * possible for it to be stuck and can't be deleted.
+			 */
+			if (sco->handle == HCI_CONN_HANDLE_UNSET)
+				hci_conn_del(sco);
+		}
 
 		/* Unacked frames */
 		hdev->acl_cnt += conn->sent;