| Message ID | 7d6f0ed3-678e-4fd5-bd64-f980e0035b87@I-love.SAKURA.ne.jp |
|---|---|
| State | New |
| Headers | show |
| Series | Bluetooth: hci_core: cancel rx_work,cmd_work,tx_work,power_on,error_reset works upon hci_unregister_dev() | expand |
Hello: This patch was applied to bluetooth/bluetooth-next.git (master) by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>: On Mon, 10 Jun 2024 20:00:32 +0900 you wrote: > 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 > > [...] Here is the summary with links: - Bluetooth: hci_core: cancel rx_work,cmd_work,tx_work,power_on,error_reset works upon hci_unregister_dev() https://git.kernel.org/bluetooth/bluetooth-next/c/5b41aa213455 You are awesome, thank you!
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index dd3b0f501018..dbbe5e2da210 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2751,7 +2751,11 @@ 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_cmd_sync_clear(hdev);
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> --- Completely untested. Please do tests with lockdep enabled before committing. Maybe it is too early to cancel hdev->{rx_work,cmd_work,tx_work}. Maybe there are more work items which should be canceled before hci_unregister_dev() completes. I don't know... net/bluetooth/hci_core.c | 4 ++++ 1 file changed, 4 insertions(+)