Bluetooth: don't try to cancel uninitialized works at mgmt_index_removed()

syzbot is reporting attempt to cancel uninitialized work at
mgmt_index_removed() [1], for calling cancel_delayed_work_sync() without
INIT_DELAYED_WORK() is not permitted.

INIT_DELAYED_WORK() is called from mgmt_init_hdev() via chan->hdev_init()
 from hci_mgmt_cmd(), but cancel_delayed_work_sync() is unconditionally
called from mgmt_index_removed().

Call cancel_delayed_work_sync() only if HCI_MGMT flag was set, for
mgmt_init_hdev() sets HCI_MGMT flag when calling INIT_DELAYED_WORK().

Link: https://syzkaller.appspot.com/bug?extid=b8ddd338a8838e581b1c
Reported-by: syzbot <syzbot+b8ddd338a8838e581b1c@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 0f1d081cd2f4f73d ("Bluetooth: Convert delayed discov_off to hci_sync")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index f0bb2fc883d7c03e2b21286299d43e38af5b6c95..6e31023b84f5fc7d5fd6ae5587672940691303cc 100644 (file)
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -8935,6 +8935,8 @@ void mgmt_index_removed(struct hci_dev *hdev)
                         HCI_MGMT_EXT_INDEX_EVENTS);
 
        /* Cancel any remaining timed work */
+       if (!hci_dev_test_flag(hdev, HCI_MGMT))
+               return;
        cancel_delayed_work_sync(&hdev->discov_off);
        cancel_delayed_work_sync(&hdev->service_cache);
        cancel_delayed_work_sync(&hdev->rpa_expired);