Deadlock Affecting kernel-rt-64k-modules package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.2% (11th percentile)

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  • Snyk IDSNYK-RHEL10-KERNELRT64KMODULES-18642808
  • published12 Aug 2026
  • disclosed10 Aug 2026

Introduced: 10 Aug 2026

NewCVE-2026-68296  (opens in a new tab)
CWE-833  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 kernel-rt-64k-modules.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-64k-modules package and not the kernel-rt-64k-modules package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

net: gre: fix lltx regression for GRE tunnels with SEQ/CSUM

Before commit 00d066a4d4ed ("netdev_features: convert NETIF_F_LLTX to dev->lltx"), NETIF_F_LLTX was set unconditionally in both __gre_tunnel_init() and ip6gre_tnl_init_features() alongside GRE_FEATURES:

dev->features |= GRE_FEATURES | NETIF_F_LLTX;

When that commit converted NETIF_F_LLTX to the dev->lltx flag, it placed 'dev->lltx = true' after the SEQ/CSUM early returns instead of before them. This causes GRE/GRETAP/ip6gre tunnels with SEQ or CSUM+encap to lose lockless TX, reintroducing _xmit_lock acquisition around their ndo_start_xmit. Since GRE xmit re-enters the stack via ip_tunnel_xmit(), holding _xmit_lock risks ABBA deadlock with the underlay device.

CPU0 CPU1


lock(&qdisc_xmit_lock_key#6); lock(&qdisc_xmit_lock_key#3); lock(&qdisc_xmit_lock_key#6); lock(&qdisc_xmit_lock_key#3);

Fix by moving dev->lltx = true before the early returns in both functions, restoring the original unconditional behavior.

CVSS Base Scores

version 3.1