Google: sys-kernel/csql-kernel-6_6, sys-kernel/lakitu-kernel-6_6, sys-kernel/lakitu-nc-kernel-6_6, sys-kernel/lakitu-vgpu-kernel-6_6, sys-kernel/tpusev-kernel-6_6: security update to 18613.613.5

medium Tenable Self-Hosted Container Security Plugin ID 465621

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

- In the Linux kernel, the following vulnerability has been resolved: quota: fix livelock between quotactl
and freeze_super When a filesystem is frozen, quotactl_block() enters a retry loop waiting for the
filesystem to thaw. It acquires s_umount, checks the freeze state, drops s_umount and uses
sb_start_write() - sb_end_write() pair to wait for the unfreeze. However, this retry loop can trigger a
livelock issue, specifically on kernels with preemption disabled. The mechanism is as follows: 1.
freeze_super() sets SB_FREEZE_WRITE and calls sb_wait_write(). 2. sb_wait_write() calls
percpu_down_write(), which initiates synchronize_rcu(). 3. Simultaneously, quotactl_block() spins in its
retry loop, immediately executing the sb_start_write() - sb_end_write() pair. 4. Because the kernel is
non-preemptible and the loop contains no scheduling points, quotactl_block() never yields the CPU. This
prevents that CPU from reaching an RCU quiescent state. 5. synchronize_rcu() in the freezer thread waits
indefinitely for the quotactl_block() CPU to report a quiescent state. 6. quotactl_block() spins
indefinitely waiting for the freezer to advance, which it cannot do as it is blocked on the RCU sync. This
results in a hang of the freezer process and 100% CPU usage by the quota process. While this can occur
intermittently on multi-core systems, it is reliably reproducing on a node with the following script,
running both the freezer and the quota toggle on the same CPU: # mkfs.ext4 -O quota /dev/sda 2g && mkdir
a_mount # mount /dev/sda -o quota,usrquota,grpquota a_mount # taskset -c 3 bash -c "while true; do
xfs_freeze -f a_mount; \ xfs_freeze -u a_mount; done" & # taskset -c 3 bash -c "while true; do quotaon
a_mount; \ quotaoff a_mount; done" & Adding cond_resched() to the retry loop fixes the issue. It acts as
an RCU quiescent state, allowing synchronize_rcu() in percpu_down_write() to complete. (CVE-2026-45895)

Solution

Update the sys-kernel/csql-kernel-6_6 library and its related packages to version 18613.613.5 or later.

Plugin Details

Severity: Medium

ID: 465621

Version: Revision 1.3

Type: Local

Family: Google COS Security Checks

Published: 10/2/2026

Updated: 10/3/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.71

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2026-45895

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 3/27/2026

Reference Information

CVE: CVE-2026-45895

Detections

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