Deadlock Affecting rv package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.03% (7th percentile)

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  • Snyk IDSNYK-RHEL10-RV-14966907
  • published16 Jan 2026
  • disclosed1 Jan 2025

Introduced: 1 Jan 2025

CVE-2025-68768  (opens in a new tab)
CWE-833  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 rv.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rv package and not the rv 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:

inet: frags: flush pending skbs in fqdir_pre_exit()

We have been seeing occasional deadlocks on pernet_ops_rwsem since September in NIPA. The stuck task was usually modprobe (often loading a driver like ipvlan), trying to take the lock as a Writer. lockdep does not track readers for rwsems so the read wasn't obvious from the reports.

On closer inspection the Reader holding the lock was conntrack looping forever in nf_conntrack_cleanup_net_list(). Based on past experience with occasional NIPA crashes I looked thru the tests which run before the crash and noticed that the crash follows ip_defrag.sh. An immediate red flag. Scouring thru (de)fragmentation queues reveals skbs sitting around, holding conntrack references.

The problem is that since conntrack depends on nf_defrag_ipv6, nf_defrag_ipv6 will load first. Since nf_defrag_ipv6 loads first its netns exit hooks run after conntrack's netns exit hook.

Flush all fragment queue SKBs during fqdir_pre_exit() to release conntrack references before conntrack cleanup runs. Also flush the queues in timer expiry handlers when they discover fqdir->dead is set, in case packet sneaks in while we're running the pre_exit flush.

The commit under Fixes is not exactly the culprit, but I think previously the timer firing would eventually unblock the spinning conntrack.

CVSS Base Scores

version 3.1