[PATCH v2] Bluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock

[PATCH v2] Bluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock

[Cen Zhang]

btintel_hw_error() issues two __hci_cmd_sync() calls (HCI_OP_RESET
and Intel exception-info retrieval) without holding
hci_req_sync_lock().  This lets it race against
hci_dev_do_close() -> btintel_shutdown_combined(), which also runs
__hci_cmd_sync() under the same lock.  When both paths manipulate
hdev->req_status/req_rsp concurrently, the close path may free the
response skb first, and the still-running hw_error path hits a
slab-use-after-free in kfree_skb().

Wrap the whole recovery sequence in hci_req_sync_lock/unlock so it
is serialized with every other synchronous HCI command issuer.

Below is the data race report and the kasan report:

  BUG: data-race in __hci_cmd_sync_sk / btintel_shutdown_combined

  read of hdev->req_rsp at net/bluetooth/hci_sync.c:199
  by task kworker/u17:1/83:
   __hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200
   __hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223
   btintel_hw_error+0x114/0x670 drivers/bluetooth/btintel.c:254
   hci_error_reset+0x348/0xa30 net/bluetooth/hci_core.c:1030

  write/free by task ioctl/22580:
   btintel_shutdown_combined+0xd0/0x360
    drivers/bluetooth/btintel.c:3648
   hci_dev_close_sync+0x9ae/0x2c10 net/bluetooth/hci_sync.c:5246
   hci_dev_do_close+0x232/0x460 net/bluetooth/hci_core.c:526

  BUG: KASAN: slab-use-after-free in
   sk_skb_reason_drop+0x43/0x380 net/core/skbuff.c:1202
  Read of size 4 at addr ffff888144a738dc
  by task kworker/u17:1/83:
   __hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200
   __hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223
   btintel_hw_error+0x186/0x670 drivers/bluetooth/btintel.c:260

Fixes: 973bb97e5aee ("Bluetooth: btintel: Add generic function for handling hardware errors")
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
---
 drivers/bluetooth/btintel.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
index 246b6205c5e0..ab146894ba4e 100644
--- a/drivers/bluetooth/btintel.c
+++ b/drivers/bluetooth/btintel.c
@@ -251,11 +251,13 @@ void btintel_hw_error(struct hci_dev *hdev, u8 code)
 
 	bt_dev_err(hdev, "Hardware error 0x%2.2x", code);
 
+	hci_req_sync_lock(hdev);
+
 	skb = __hci_cmd_sync(hdev, HCI_OP_RESET, 0, NULL, HCI_INIT_TIMEOUT);
 	if (IS_ERR(skb)) {
 		bt_dev_err(hdev, "Reset after hardware error failed (%ld)",
 			   PTR_ERR(skb));
-		return;
+		goto unlock;
 	}
 	kfree_skb(skb);
 
@@ -263,18 +265,21 @@ void btintel_hw_error(struct hci_dev *hdev, u8 code)
 	if (IS_ERR(skb)) {
 		bt_dev_err(hdev, "Retrieving Intel exception info failed (%ld)",
 			   PTR_ERR(skb));
-		return;
+		goto unlock;
 	}
 
 	if (skb->len != 13) {
 		bt_dev_err(hdev, "Exception info size mismatch");
 		kfree_skb(skb);
-		return;
+		goto unlock;
 	}
 
 	bt_dev_err(hdev, "Exception info %s", (char *)(skb->data + 1));
 
 	kfree_skb(skb);
+
+unlock:
+	hci_req_sync_unlock(hdev);
 }
 EXPORT_SYMBOL_GPL(btintel_hw_error);
 
-- 
2.34.1

RE: [v2] Bluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock

[bluez.test.bot]

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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=1068649

---Test result---

Test Summary:
CheckPatch                    PENDING   0.58 seconds
GitLint                       PENDING   0.35 seconds
SubjectPrefix                 PASS      0.08 seconds
BuildKernel                   PASS      27.17 seconds
CheckAllWarning               PASS      29.65 seconds
CheckSparse                   PASS      28.44 seconds
BuildKernel32                 PASS      26.84 seconds
TestRunnerSetup               PASS      584.05 seconds
TestRunner_l2cap-tester       PASS      28.26 seconds
TestRunner_iso-tester         FAIL      32.95 seconds
TestRunner_bnep-tester        PASS      6.39 seconds
TestRunner_mgmt-tester        FAIL      117.46 seconds
TestRunner_rfcomm-tester      PASS      9.95 seconds
TestRunner_sco-tester         FAIL      14.94 seconds
TestRunner_ioctl-tester       PASS      10.54 seconds
TestRunner_mesh-tester        FAIL      12.49 seconds
TestRunner_smp-tester         PASS      8.79 seconds
TestRunner_userchan-tester    PASS      6.97 seconds
IncrementalBuild              PENDING   0.88 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       0.109 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    2.600 seconds
Mesh - Send cancel - 2                               Timed out    1.993 seconds
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:



---
Regards,
Linux Bluetooth

Re: [PATCH v2] Bluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock

[patchwork-bot+bluetooth]

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Wed, 18 Mar 2026 20:54:03 +0800 you wrote:
> btintel_hw_error() issues two __hci_cmd_sync() calls (HCI_OP_RESET
> and Intel exception-info retrieval) without holding
> hci_req_sync_lock().  This lets it race against
> hci_dev_do_close() -> btintel_shutdown_combined(), which also runs
> __hci_cmd_sync() under the same lock.  When both paths manipulate
> hdev->req_status/req_rsp concurrently, the close path may free the
> response skb first, and the still-running hw_error path hits a
> slab-use-after-free in kfree_skb().
> 
> [...]

Here is the summary with links:
  - [v2] Bluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock
    https://git.kernel.org/bluetooth/bluetooth-next/c/b8982b6b9815

You are awesome, thank you!
-- 
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