Date:   Tue, 21 Feb 2023 16:09:14 -0800
In-Reply-To: <20230222000915.2843208-1-jiangzp@google.com>
Mime-Version: 1.0
References: <20230222000915.2843208-1-jiangzp@google.com>
Message-ID: <20230221160910.kernel.v1.1.If0578b001c1f12567f2ebcac5856507f1adee745@changeid>
Subject: [kernel PATCH v1 1/1] Bluetooth: hci_sync: clear workqueue before
 clear mgmt cmd
From:   Zhengping Jiang <jiangzp@google.com>
To:     linux-bluetooth@vger.kernel.org, marcel@holtmann.org,
        luiz.dentz@gmail.com
Cc:     chromeos-bluetooth-upstreaming@chromium.org, mmandlik@google.com,
        Zhengping Jiang <jiangzp@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Clear cmd_sync_work queue before clearing the mgmt cmd list to avoid
racing conditions which cause use-after-free.

When powering off the adapter, the mgmt cmd list will be cleared. If a
work is queued in the cmd_sync_work queue at the same time, it will
cause the risk of use-after-free, as the cmd pointer is not checked
before use.

Signed-off-by: Zhengping Jiang <jiangzp@google.com>
---

Changes in v1:
- Clear cmd_sync_work queue before clearing the mgmt cmd list

 net/bluetooth/hci_sync.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 117eedb6f709..6609434e3125 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -4840,6 +4840,8 @@ int hci_dev_close_sync(struct hci_dev *hdev)
 
 	auto_off = hci_dev_test_and_clear_flag(hdev, HCI_AUTO_OFF);
 
+	hci_cmd_sync_clear(hdev);
+
 	if (!auto_off && hdev->dev_type == HCI_PRIMARY &&
 	    !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
 	    hci_dev_test_flag(hdev, HCI_MGMT))
-- 
2.39.2.637.g21b0678d19-goog