CVE-2025-40061: RDMA/rxe: Fix race in do_task() when draining
In the Linux kernel, the following vulnerability has been resolved:
RDMA/rxe: Fix race in dotask() when draining
When dotask() exhausts its iteration budget (!ret), it sets the state to TASKSTATEIDLE to reschedule, without a secondary check on the current task->state. This can overwrite the TASKSTATEDRAINING state set by a concurrent call to rxecleanuptask() or rxedisabletask().
While state changes are protected by a spinlock, both rxecleanuptask() and rxedisabletask() release the lock while waiting for the task to finish draining in the while(!isdone(task)) loop. The race occurs if dotask() 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 TASKSTATEDRAINING 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 TASKSTATEDRAINED, stopping the task as intended.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1052.55+fips1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.17.0-14.14 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.17.0-1007.7 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.17.0-1008.8 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.17.0-1007.7 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.17.0-1007.7 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 6.17.0-1008.8 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.17.0-1006.7 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 6.17.0-14.14.1 - Compensating control
Restore the pre-migration draining behavior in RDMA/rxe do_task(): when iterations are exhausted (!ret) and task->state is TASK_STATE_DRAINING, set cont to 1 to force a new loop iteration, allowing the task to transition to TASK_STATE_DRAINED instead of rescheduling as TASK_STATE_IDLE.
Event History
Frequently Asked Questions
What is the severity of CVE-2025-40061?
CVE-2025-40061 has been classified as a moderate severity vulnerability in the Linux kernel.
How do I fix CVE-2025-40061?
To fix CVE-2025-40061, update your Linux kernel to the latest version provided by your distribution that includes the patch for this vulnerability.
What are the potential impacts of CVE-2025-40061?
The potential impacts of CVE-2025-40061 include race conditions in task scheduling, possibly leading to unexpected behavior in RDMA operations.
Which systems are affected by CVE-2025-40061?
CVE-2025-40061 affects versions of the Linux kernel that implement RDMA with the rxe driver.
Is there a workaround for CVE-2025-40061?
There are no known effective workarounds for CVE-2025-40061, and updating the kernel is the recommended course of action.