[PATCH] Bluetooth: coredump: Don't leak an active dump when the device is opened

["Ali Ahmet Memiş" <aliamemis@disroot.org>]

If the device is closed during a dump and opened again before the dump
timeout fires, hci_devcd_reset() in hci_dev_open_sync() clears
dump.head and cancels the timeout without freeing the buffer, so it is
leaked.

Free it instead after making sure the timeout is not running.

Fixes: 9695ef876fd1 ("Bluetooth: Add support for hci devcoredump")
Signed-off-by: Ali Ahmet Memiş <aliamemis@disroot.org>
---
On top of 860b93123309 ("Bluetooth: hci_sync: Serialize devcoredump
reset during device open")

Tested with hci_vhci.  force_devcoredump in TIMEOUT state, then
"hciconfig hci0 up" before the timeout.  Without the patch the buffer
stays in /proc/vmallocinfo, with it it is freed.

 include/net/bluetooth/coredump.h | 2 ++
 net/bluetooth/coredump.c         | 9 +++++++++
 net/bluetooth/hci_sync.c         | 4 +---
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/include/net/bluetooth/coredump.h b/include/net/bluetooth/coredump.h
index acc1849f6..b8bba9a8b 100644
--- a/include/net/bluetooth/coredump.h
+++ b/include/net/bluetooth/coredump.h
@@ -70,6 +70,7 @@ struct hci_devcoredump {
 const char *hci_devcd_state_name(enum devcoredump_state state);
 
 void hci_devcd_reset(struct hci_dev *hdev);
+void hci_devcd_discard(struct hci_dev *hdev);
 void hci_devcd_shutdown(struct hci_dev *hdev);
 void hci_devcd_rx(struct work_struct *work);
 void hci_devcd_timeout(struct work_struct *work);
@@ -90,6 +91,7 @@ static inline const char *hci_devcd_state_name(enum devcoredump_state state)
 }
 
 static inline void hci_devcd_reset(struct hci_dev *hdev) {}
+static inline void hci_devcd_discard(struct hci_dev *hdev) {}
 static inline void hci_devcd_shutdown(struct hci_dev *hdev) {}
 static inline void hci_devcd_rx(struct work_struct *work) {}
 static inline void hci_devcd_timeout(struct work_struct *work) {}
diff --git a/net/bluetooth/coredump.c b/net/bluetooth/coredump.c
index 71fc8dab4..b4283e6ae 100644
--- a/net/bluetooth/coredump.c
+++ b/net/bluetooth/coredump.c
@@ -104,6 +104,15 @@ static void hci_devcd_free(struct hci_dev *hdev)
 	hci_devcd_reset(hdev);
 }
 
+void hci_devcd_discard(struct hci_dev *hdev)
+{
+	cancel_delayed_work_sync(&hdev->dump.dump_timeout);
+
+	hci_dev_lock(hdev);
+	hci_devcd_free(hdev);
+	hci_dev_unlock(hdev);
+}
+
 void hci_devcd_shutdown(struct hci_dev *hdev)
 {
 	unsigned long flags;
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index efbd2e538..cc2f81b62 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -5503,9 +5503,7 @@ int hci_dev_open_sync(struct hci_dev *hdev)
 		goto done;
 	}
 
-	hci_dev_lock(hdev);
-	hci_devcd_reset(hdev);
-	hci_dev_unlock(hdev);
+	hci_devcd_discard(hdev);
 
 	set_bit(HCI_RUNNING, &hdev->flags);
 	hci_sock_dev_event(hdev, HCI_DEV_OPEN);
-- 
2.55.0