CVE-2026-93091firmware: arm_scmi: Quiesce notifications before teardown

Official description

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Quiesce notifications before teardown scmi_notification_exit() clears and releases the notification instance, but transport callbacks can still deliver incoming notifications until the TX/RX channels are freed. During remove, an RX interrupt in that window can enter scmi_notify() while notification state is being torn down and then dereference freed memory. The same ordering exists on the probe error path after notification initialization. The notification late-init worker has a separate lifetime issue: protocol event registration queues ni->init_work on the system workqueue, so destroying ni->notify_wq does not drain that work. If the devres group is released while init_work is still pending or running, the late-init worker can dereference the freed notification instance. Quiesce the notification core before TX/RX channels are torn down, then clean up the channels before releasing the notification core resources. Use disable_work_sync() so future late-init queueing is rejected and any already queued or running late-init work has completed before channel teardown starts.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/6778bcabd2e0c32f73476f0bc6369013692540be
• https://git.kernel.org/stable/c/2aac23bc0a79af41104d99823bb250fae92ba144
• https://git.kernel.org/stable/c/5e30d3d16d1a9e599be4dcea872874e65e2c277b
• https://git.kernel.org/stable/c/8e49055d0d495c9c07575ad8e111d9eaf0efb13f