CVE-2026-98749: tty: serial: max3100: shut down timer before freeing port
In the Linux kernel, the following vulnerability has been resolved:
tty: serial: max3100: shut down timer before freeing port
max3100shutdown() stops the polling timer but returns early during system suspend. If the SPI device is unbound before resume, the serial core does not call max3100shutdown() again, so max3100remove() frees the port while the timer remains armed. max3100timeout() may then access the freed port and re-arm the timer.
Add final timer teardown to max3100remove() and use timershutdownsync() to prevent a racing callback from re-arming it. Also free the IRQ and destroy the workqueue there before freeing the port. Keep timerdeletesync() in max3100shutdown() so that a subsequent open() can re-arm the timer.
The workqueue is created before requestirq() and destroyed on both requestirq() failure and normal shutdown. Its presence at remove thus identifies the IRQ left registered when suspend bypasses shutdown.
Free the IRQ before destroying the workqueue, in both max3100shutdown() and max3100remove(), and cancel the pending work in between. freeirq() waits for a running interrupt handler to finish and no new handler can start afterwards, so a racing handler cannot queue work on a workqueue that is being destroyed; the forceendwork check in max3100dowork() only narrows that window, as a handler delayed between the check and queuework() could still run after the teardown has cleared the workqueue pointer. Cancelling the work also keeps destroyworkqueue() from waiting on a queued work item in case remove() ever runs while the freezable workqueue is still frozen, e.g. device removal during the resume window, before workqueues are thawed.
This issue was found by an in-house static analysis tool.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
In the max3100 driver teardown, use timer_shutdown_sync() in max3100_remove() before freeing the port; cancel pending work, call free_irq() before destroy_workqueue(), and destroy the workqueue on both request_irq() failure and normal shutdown. Keep timer_delete_sync() in max3100_shutdown().