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

[Tristan Madani <tristmd@gmail.com>]

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