In the Linux kernel, the following vulnerability has been resolved:
xfrm: avoid lock inversion in nat keepalive work
nat_keepalive_work() walks the state table while xfrm_state_walk()
holds net->xfrm.xfrm_state_lock. Its callback then acquires x->lock,
which conflicts with the delete path taking the same locks in reverse
order via xfrm_state_delete() and __xfrm_state_delete(). This creates
an AB-BA deadlock that is reported by lockdep when a NAT keepalive
worker races with SA deletion.
Fix this by splitting the keepalive walk into two phases. First,
collect the candidate states while the walk holds xfrm_state_lock and
take a reference on each state. Then, after the walk completes, process
each collected state and acquire x->lock without nesting it under
xfrm_state_lock.
xfrm: avoid lock inversion in nat keepalive work
nat_keepalive_work() walks the state table while xfrm_state_walk()
holds net->xfrm.xfrm_state_lock. Its callback then acquires x->lock,
which conflicts with the delete path taking the same locks in reverse
order via xfrm_state_delete() and __xfrm_state_delete(). This creates
an AB-BA deadlock that is reported by lockdep when a NAT keepalive
worker races with SA deletion.
Fix this by splitting the keepalive walk into two phases. First,
collect the candidate states while the walk holds xfrm_state_lock and
take a reference on each state. Then, after the walk completes, process
each collected state and acquire x->lock without nesting it under
xfrm_state_lock.
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 04 Sep 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: xfrm: avoid lock inversion in nat keepalive work nat_keepalive_work() walks the state table while xfrm_state_walk() holds net->xfrm.xfrm_state_lock. Its callback then acquires x->lock, which conflicts with the delete path taking the same locks in reverse order via xfrm_state_delete() and __xfrm_state_delete(). This creates an AB-BA deadlock that is reported by lockdep when a NAT keepalive worker races with SA deletion. Fix this by splitting the keepalive walk into two phases. First, collect the candidate states while the walk holds xfrm_state_lock and take a reference on each state. Then, after the walk completes, process each collected state and acquire x->lock without nesting it under xfrm_state_lock. | |
| Title | xfrm: avoid lock inversion in nat keepalive work | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-04T15:54:55.489Z
Reserved: 2026-08-26T14:34:25.797Z
Link: CVE-2026-80845
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-04T16:18:13.173
Modified: 2026-09-04T16:18:13.173
Link: CVE-2026-80845
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.