4.19-stable review patch. If anyone has any objections, please let me know.
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From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
[ Upstream commit 0d151a103775dd9645c78c97f77d6e2a5298d913 ]
syzbot is reporting that calling hci_release_dev() from hci_error_reset() due to hci_dev_put() from hci_error_reset() can cause deadlock at destroy_workqueue(), for hci_error_reset() is called from hdev->req_workqueue which destroy_workqueue() needs to flush.
We need to make sure that hdev->{rx_work,cmd_work,tx_work} which are queued into hdev->workqueue and hdev->{power_on,error_reset} which are queued into hdev->req_workqueue are no longer running by the moment
destroy_workqueue(hdev->workqueue); destroy_workqueue(hdev->req_workqueue);
are called from hci_release_dev().
Call cancel_work_sync() on these work items from hci_unregister_dev() as soon as hdev->list is removed from hci_dev_list.
Reported-by: syzbot syzbot+da0a9c9721e36db712e8@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=da0a9c9721e36db712e8 Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/bluetooth/hci_core.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 47f1eec0eb35f..504f6aa4e95db 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -3288,7 +3288,11 @@ void hci_unregister_dev(struct hci_dev *hdev) list_del(&hdev->list); write_unlock(&hci_dev_list_lock);
+ cancel_work_sync(&hdev->rx_work); + cancel_work_sync(&hdev->cmd_work); + cancel_work_sync(&hdev->tx_work); cancel_work_sync(&hdev->power_on); + cancel_work_sync(&hdev->error_reset);
hci_dev_do_close(hdev);