net/packet: defer vmalloc TX_RING free until skbs finish
Summary
| CVE | CVE-2026-80841 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-04 16:18:12 UTC |
| Updated | 2026-09-04 16:18:12 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: net/packet: defer vmalloc TX_RING free until skbs finish AF_PACKET TX_RING skbs keep a raw pointer to their ring frame. The skb page references preserve page-backed ring blocks after pg_vec is freed, but they do not preserve a vmalloc mapping. tpacket_destruct_skb() currently drops the pending reference before writing the timestamp and TP_STATUS_AVAILABLE to the frame. Move the decrement after those stores. The smp_wmb() in __packet_set_status() orders the frame stores before the decrement. Also recheck pending TX frames under pg_vec_lock before non-closing ring replacement, so a racing send cannot add a pending skb between the initial check and the ring swap. Ring allocation can produce a mixture of page-backed and vmalloc-backed blocks. Allocate deferred-work storage during TX ring setup when the first vmalloc-backed block is encountered, and keep its pointer in the pg_vec allocation header. If allocation fails, return -ENOMEM from ring setup. On socket close, a non-NULL pointer identifies a vmalloc-backed vector without a scan. If TX skbs remain, defer the whole vector to system_long_wq. After pg_vec is detached, a late destructor can skip the pending decrement. Use socket write-memory accounting as the deferred lifetime gate instead: an skb remains charged through its final sock_wfree(), after all ring-frame accesses. The delayed work retains a socket reference and reschedules itself until no TX skbs remain. Move pending_refcnt release to packet_sock_destruct() so late skb destructors and deferred cleanup can safely use it after packet_release(). Page-backed teardown remains synchronous, and no lock is added to the TX completion hot path. |
Risk And Classification
EPSS: 0.001660000 probability, percentile 0.061330000 (date 2026-09-07)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected b013840810c221f2b0cf641d01531526052dc1fb 0189dce07db2dc059ae0570e06758ec4233c6e11 git | Not specified |
| CNA | Linux | Linux | affected b013840810c221f2b0cf641d01531526052dc1fb 550d00aa58193fb649a09a9c9e338c685adad784 git | Not specified |
| CNA | Linux | Linux | affected b013840810c221f2b0cf641d01531526052dc1fb 992cc9f94ca924089a506ba9b327caa9af797529 git | Not specified |
| CNA | Linux | Linux | affected 3.14 | Not specified |
| CNA | Linux | Linux | unaffected 3.14 semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.13 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.3 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/0189dce07db2dc059ae0570e06758ec4233c6e11 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/550d00aa58193fb649a09a9c9e338c685adad784 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/992cc9f94ca924089a506ba9b327caa9af797529 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.