CVE-2025-38534: netfs: Fix copy-to-cache so that it performs collection with ceph+fscache
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix copy-to-cache so that it performs collection with ceph+fscache
The netfs copy-to-cache that is used by Ceph with local caching sets up a new request to write data just read to the cache. The request is started and then left to look after itself whilst the app continues. The request gets notified by the backing fs upon completion of the async DIO write, but then tries to wake up the app because NETFSRREQOFFLOADCOLLECTION isn't set - but the app isn't waiting there, and so the request just hangs.
Fix this by setting NETFSRREQOFFLOADCOLLECTION which causes the notification from the backing filesystem to put the collection onto a work queue instead.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-aws-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1017.17~24.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1017.17~24.04.1 - Upgrade
Upgrade
ubuntu/linux-gcp-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1020.21~24.04.1 - Upgrade
Upgrade
ubuntu/linux-oem-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1016.16 - Upgrade
Upgrade
ubuntu/linux-oracle-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1017.17~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-36.36.1~24.04.1 - Upgrade
Upgrade
ubuntu/linux-realtime-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1016.16~24.04.1 - Configuration
Set NETFS_RREQ_OFFLOAD_COLLECTION so that notifications from the backing filesystem put collection onto a work queue instead of attempting to wake the application.
Linux kernel netfs copy-to-cache NETFS_RREQ_OFFLOAD_COLLECTION = set
Event History
Frequently Asked Questions
What is the severity of CVE-2025-38534?
CVE-2025-38534 is classified as a low severity vulnerability in the Linux kernel.
How do I fix CVE-2025-38534?
To fix CVE-2025-38534, update your Linux kernel to the latest stable version provided by your distribution.
What does CVE-2025-38534 affect?
CVE-2025-38534 affects the netfs component of the Linux kernel, specifically related to local caching with Ceph.
Is CVE-2025-38534 exploitable?
While CVE-2025-38534 has been fixed, its potential exploitability depends on the usage and configuration of Ceph with local caching.
What is the impact of CVE-2025-38534?
The impact of CVE-2025-38534 includes potential issues with data caching and integrity when using Ceph in the Linux kernel.