CVE-2025-40061: RDMA/rxe: Fix race in do_task() when draining

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-28 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix race in do_task() when draining When do_task() exhausts its iteration budget (!ret), it sets the state to TASK_STATE_IDLE to reschedule, without a secondary check on the current task->state. This can overwrite the TASK_STATE_DRAINING state set by a concurrent call to rxe_cleanup_task() or rxe_disable_task(). While state changes are protected by a spinlock, both rxe_cleanup_task() and rxe_disable_task() release the lock while waiting for the task to finish draining in the while(!is_done(task)) loop. The race occurs if do_task() hits its iteration limit and acquires the lock in this window. The cleanup logic may then proceed while the task incorrectly reschedules itself, leading to a potential use-after-free. This bug was introduced during the migration from tasklets to workqueues, where the special handling for the draining case was lost. Fix this by restoring the original pre-migration behavior. If the state is TASK_STATE_DRAINING when iterations are exhausted, set cont to 1 to force a new loop iteration. This allows the task to finish its work, so that a subsequent iteration can reach the switch statement and correctly transition the state to TASK_STATE_DRAINED, stopping the task as intended.

Affected products

Linux kernel: 6.5 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

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