Bluetooth: cancel devcoredump work during device teardown

[PATCH bluetooth] Bluetooth: cancel devcoredump work during device teardown

Posted by Tristan Madani 1 month, 2 weeks ago

From: Tristan Madani <tristan@talencesecurity.com>

hci_devcd_setup() initializes dump_timeout and dump_rx work items
during device allocation, but hci_unregister_dev() does not cancel
them before the device is freed. If a devcoredump is in progress
when the device is unregistered, the dump_timeout delayed work timer
remains active. When it fires after hci_release_dev() frees the
hci_dev struct, it accesses freed memory.

Add hci_devcd_destroy() to disable dump work items and purge the
dump queue, called from hci_unregister_dev() alongside the existing
disable_work_sync() calls.

Fixes: 9695ef876fd1 ("Bluetooth: Add support for hci devcoredump")
Cc: stable@vger.kernel.org
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
---
 include/net/bluetooth/hci_core.h | 9 +++++++++
 net/bluetooth/hci_core.c         | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 3df59849dcbea..5a60c3f94a462 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -1800,6 +1800,15 @@ static inline void hci_devcd_setup(struct hci_dev *hdev)
 #endif
 }
 
+static inline void hci_devcd_destroy(struct hci_dev *hdev)
+{
+#ifdef CONFIG_DEV_COREDUMP
+	disable_delayed_work_sync(&hdev->dump.dump_timeout);
+	disable_work_sync(&hdev->dump.dump_rx);
+	skb_queue_purge(&hdev->dump.dump_q);
+#endif
+}
+
 int hci_dev_open(__u16 dev);
 int hci_dev_close(__u16 dev);
 int hci_dev_do_close(struct hci_dev *hdev);
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 5ba9fe8261ec8..d4d559dabf422 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2671,6 +2671,8 @@ void hci_unregister_dev(struct hci_dev *hdev)
 	disable_delayed_work_sync(&hdev->cmd_timer);
 	disable_delayed_work_sync(&hdev->ncmd_timer);
 
+	hci_devcd_destroy(hdev);
+
 	hci_cmd_sync_clear(hdev);
 
 	hci_unregister_suspend_notifier(hdev);
-- 
2.47.3

Re: [PATCH bluetooth] Bluetooth: cancel devcoredump work during device teardown

Posted by Luiz Augusto von Dentz 1 month, 1 week ago

Hi Tristan,

On Fri, Aug 14, 2026 at 7:12 PM Tristan Madani <tristmd@gmail.com> wrote:
>
> From: Tristan Madani <tristan@talencesecurity.com>
>
> hci_devcd_setup() initializes dump_timeout and dump_rx work items
> during device allocation, but hci_unregister_dev() does not cancel
> them before the device is freed. If a devcoredump is in progress
> when the device is unregistered, the dump_timeout delayed work timer
> remains active. When it fires after hci_release_dev() frees the
> hci_dev struct, it accesses freed memory.
>
> Add hci_devcd_destroy() to disable dump work items and purge the
> dump queue, called from hci_unregister_dev() alongside the existing
> disable_work_sync() calls.
>
> Fixes: 9695ef876fd1 ("Bluetooth: Add support for hci devcoredump")
> Cc: stable@vger.kernel.org
> Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
> ---
>  include/net/bluetooth/hci_core.h | 9 +++++++++
>  net/bluetooth/hci_core.c         | 2 ++
>  2 files changed, 11 insertions(+)
>
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index 3df59849dcbea..5a60c3f94a462 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -1800,6 +1800,15 @@ static inline void hci_devcd_setup(struct hci_dev *hdev)
>  #endif
>  }
>
> +static inline void hci_devcd_destroy(struct hci_dev *hdev)
> +{
> +#ifdef CONFIG_DEV_COREDUMP
> +       disable_delayed_work_sync(&hdev->dump.dump_timeout);
> +       disable_work_sync(&hdev->dump.dump_rx);
> +       skb_queue_purge(&hdev->dump.dump_q);
> +#endif
> +}
> +
>  int hci_dev_open(__u16 dev);
>  int hci_dev_close(__u16 dev);
>  int hci_dev_do_close(struct hci_dev *hdev);
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 5ba9fe8261ec8..d4d559dabf422 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -2671,6 +2671,8 @@ void hci_unregister_dev(struct hci_dev *hdev)
>         disable_delayed_work_sync(&hdev->cmd_timer);
>         disable_delayed_work_sync(&hdev->ncmd_timer);
>
> +       hci_devcd_destroy(hdev);
> +
>         hci_cmd_sync_clear(hdev);
>
>         hci_unregister_suspend_notifier(hdev);
> --
> 2.47.3

Sashiko found 2 issues, both seem valid to me:

https://sashiko.dev/#/patchset/20260814182849.940976-1-ali%40iusegentoo.com

-- 
Luiz Augusto von Dentz