Overview
About vulnerability
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.
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 5.14.0 (+1 more)
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.