Bluetooth: use hdev->workqueue when queuing hdev->{cmd,ncmd}_timer works
syzbot is reporting attempt to schedule hdev->cmd_work work from system_wq WQ into hdev->workqueue WQ which is under draining operation [1], for commitc8efcc2589
("workqueue: allow chained queueing during destruction") does not allow such operation. The check introduced by commit877afadad2
("Bluetooth: When HCI work queue is drained, only queue chained work") was incomplete. Use hdev->workqueue WQ when queuing hdev->{cmd,ncmd}_timer works because hci_{cmd,ncmd}_timeout() calls queue_work(hdev->workqueue). Also, protect the queuing operation with RCU read lock in order to avoid calling queue_delayed_work() after cancel_delayed_work() completed. Link: https://syzkaller.appspot.com/bug?extid=243b7d89777f90f7613b [1] Reported-by: syzbot <syzbot+243b7d89777f90f7613b@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Fixes:877afadad2
("Bluetooth: When HCI work queue is drained, only queue chained work") Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Родитель
2d2cb3066f
Коммит
deee93d13d
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@ -597,6 +597,15 @@ static int hci_dev_do_reset(struct hci_dev *hdev)
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/* Cancel these to avoid queueing non-chained pending work */
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hci_dev_set_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE);
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/* Wait for
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*
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* if (!hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE))
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* queue_delayed_work(&hdev->{cmd,ncmd}_timer)
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*
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* inside RCU section to see the flag or complete scheduling.
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*/
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synchronize_rcu();
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/* Explicitly cancel works in case scheduled after setting the flag. */
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cancel_delayed_work(&hdev->cmd_timer);
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cancel_delayed_work(&hdev->ncmd_timer);
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@ -4063,12 +4072,14 @@ static void hci_cmd_work(struct work_struct *work)
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if (res < 0)
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__hci_cmd_sync_cancel(hdev, -res);
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rcu_read_lock();
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if (test_bit(HCI_RESET, &hdev->flags) ||
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hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE))
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cancel_delayed_work(&hdev->cmd_timer);
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else
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schedule_delayed_work(&hdev->cmd_timer,
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HCI_CMD_TIMEOUT);
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queue_delayed_work(hdev->workqueue, &hdev->cmd_timer,
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HCI_CMD_TIMEOUT);
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rcu_read_unlock();
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} else {
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skb_queue_head(&hdev->cmd_q, skb);
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queue_work(hdev->workqueue, &hdev->cmd_work);
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@ -3767,16 +3767,18 @@ static inline void handle_cmd_cnt_and_timer(struct hci_dev *hdev, u8 ncmd)
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{
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cancel_delayed_work(&hdev->cmd_timer);
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rcu_read_lock();
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if (!test_bit(HCI_RESET, &hdev->flags)) {
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if (ncmd) {
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cancel_delayed_work(&hdev->ncmd_timer);
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atomic_set(&hdev->cmd_cnt, 1);
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} else {
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if (!hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE))
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schedule_delayed_work(&hdev->ncmd_timer,
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HCI_NCMD_TIMEOUT);
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queue_delayed_work(hdev->workqueue, &hdev->ncmd_timer,
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HCI_NCMD_TIMEOUT);
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}
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}
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rcu_read_unlock();
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}
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static u8 hci_cc_le_read_buffer_size_v2(struct hci_dev *hdev, void *data,
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