[PATCH] Bluetooth: hci_core: Fix queuing rx_work after workqueue is drained

[PATCH] Bluetooth: hci_core: Fix queuing rx_work after workqueue is drained

[Shuai Liu]

hci_recv_frame() and hci_recv_diag() queue hdev->rx_work unconditionally.
They can run from the driver RX path (e.g. vhci_write) while
hci_dev_close_sync() is draining hdev->workqueue (HCIDEVDOWN racing with
a driver write). Since that queue_work() is not chained work from the
rx_work worker itself, __queue_work() sees the queue marked __WQ_DRAINING,
warns "cannot queue %ps on wq %s", and drops the work:

  workqueue: cannot queue hci_rx_work on wq hci0
  WARNING: kernel/workqueue.c:2436 at __queue_work
  Call Trace:
   queue_work_on
   hci_recv_frame
   vhci_write

hci_dev_close_sync() already sets HCI_CMD_DRAIN_WORKQUEUE before
draining. Route the rx_work producers through the same guard via a
shared hci_sched_rx() helper, mirroring the existing hci_sched_tx()
fix for tx_work.

Fixes: 525daaea459f ("Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close")
Reported-by: syzbot+2344fb8002f3ef5b1712@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2344fb8002f3ef5b1712
Signed-off-by: Shuai Liu <847807867@qq.com>
---
 net/bluetooth/hci_core.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 209244fd9391..dd6bc1628bca 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2892,6 +2892,17 @@ static u8 hci_dev_classify_pkt_type(struct hci_dev *hdev, struct sk_buff *skb)
 	return hci_skb_pkt_type(skb);
 }
 
+/* Queue hdev->rx_work, unless hdev->workqueue is being drained by
+ * hci_dev_close_sync(), which would otherwise WARN and drop the work.
+ */
+static void hci_sched_rx(struct hci_dev *hdev)
+{
+	rcu_read_lock();
+	if (!hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE))
+		queue_work(hdev->workqueue, &hdev->rx_work);
+	rcu_read_unlock();
+}
+
 /* Receive frame from HCI drivers */
 int hci_recv_frame(struct hci_dev *hdev, struct sk_buff *skb)
 {
@@ -2945,7 +2956,7 @@ int hci_recv_frame(struct hci_dev *hdev, struct sk_buff *skb)
 	__net_timestamp(skb);
 
 	skb_queue_tail(&hdev->rx_q, skb);
-	queue_work(hdev->workqueue, &hdev->rx_work);
+	hci_sched_rx(hdev);
 
 	return 0;
 }
@@ -2961,7 +2972,7 @@ int hci_recv_diag(struct hci_dev *hdev, struct sk_buff *skb)
 	__net_timestamp(skb);
 
 	skb_queue_tail(&hdev->rx_q, skb);
-	queue_work(hdev->workqueue, &hdev->rx_work);
+	hci_sched_rx(hdev);
 
 	return 0;
 }
-- 
2.53.0

RE: Bluetooth: hci_core: Fix queuing rx_work after workqueue is drained

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 1606 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/series/1192220/

---Test result---

Test Summary:
CheckPatch                    PASS      0.79 seconds
VerifyFixes                   PASS      0.13 seconds
VerifySignedoff               PASS      0.13 seconds
GitLint                       PASS      0.35 seconds
SubjectPrefix                 PASS      0.13 seconds
BuildKernel                   PASS      29.76 seconds
CheckAllWarning               PASS      34.03 seconds
CheckSparse                   PASS      36.64 seconds
BuildKernel32                 PASS      29.87 seconds
CheckKernelLLVM               PASS      33.89 seconds
TestRunnerSetup               PASS      708.61 seconds
TestRunner_l2cap-tester       PASS      12.78 seconds
TestRunner_iso-tester         PASS      10.75 seconds
TestRunner_bnep-tester        PASS      3.16 seconds
TestRunner_mgmt-tester        PASS      87.80 seconds
TestRunner_rfcomm-tester      PASS      4.53 seconds
TestRunner_sco-tester         PASS      5.68 seconds
TestRunner_ioctl-tester       PASS      4.69 seconds
TestRunner_mesh-tester        PASS      5.59 seconds
TestRunner_smp-tester         PASS      4.44 seconds
TestRunner_userchan-tester    PASS      3.28 seconds
TestRunner_6lowpan-tester     PASS      11.92 seconds
IncrementalBuild              PASS      28.71 seconds



https://github.com/bluez/bluetooth-next/pull/989

---
Regards,
Linux Bluetooth