In the Linux kernel, the following vulnerability has been resolved:
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 commit c8efcc2589464ac7 ("workqueue: allow chained queueing during destruction") does not allow such operation.
The check introduced by commit 877afadad2dce8aa ("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.
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Dec 31, 2025 | Dec 31, 2025 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Dec 30, 2025 |
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