Google: sys-kernel/csql-kernel-6_1, sys-kernel/lakitu-kernel-6_1: security update to 18244.85.5

high Tenable Self-Hosted Container Security Plugin ID 450653

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: KVM: Always flush async #PF workqueue
when vCPU is being destroyed Always flush the per-vCPU async #PF workqueue when a vCPU is clearing its
completion queue, e.g. when a VM and all its vCPUs is being destroyed. KVM must ensure that none of its
workqueue callbacks is running when the last reference to the KVM _module_ is put. Gifting a reference to
the associated VM prevents the workqueue callback from dereferencing freed vCPU/VM memory, but does not
prevent the KVM module from being unloaded before the callback completes. Drop the misguided VM refcount
gifting, as calling kvm_put_kvm() from async_pf_execute() if kvm_put_kvm() flushes the async #PF workqueue
will result in deadlock. async_pf_execute() can't return until kvm_put_kvm() finishes, and kvm_put_kvm()
can't return until async_pf_execute() finishes: WARNING: CPU: 8 PID: 251 at virt/kvm/kvm_main.c:1435
kvm_put_kvm+0x2d/0x320 [kvm] Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel kvm irqbypass
CPU: 8 PID: 251 Comm: kworker/8:1 Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 Hardware name: QEMU
Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: events async_pf_execute [kvm] RIP:
0010:kvm_put_kvm+0x2d/0x320 [kvm] Call Trace: <TASK> async_pf_execute+0x198/0x260 [kvm]
process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50
ret_from_fork_asm+0x11/0x20 </TASK> ---[ end trace 0000000000000000 ]--- INFO: task kworker/8:1:251
blocked for more than 120 seconds. Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/8:1 state:D stack:0 pid:251
ppid:2 flags:0x00004000 Workqueue: events async_pf_execute [kvm] Call Trace: <TASK> __schedule+0x33f/0xa40
schedule+0x53/0xc0 schedule_timeout+0x12a/0x140 __wait_for_common+0x8d/0x1d0
__flush_work.isra.0+0x19f/0x2c0 kvm_clear_async_pf_completion_queue+0x129/0x190 [kvm]
kvm_arch_destroy_vm+0x78/0x1b0 [kvm] kvm_put_kvm+0x1c1/0x320 [kvm] async_pf_execute+0x198/0x260 [kvm]
process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50
ret_from_fork_asm+0x11/0x20 </TASK> If kvm_clear_async_pf_completion_queue() actually flushes the
workqueue, then there's no need to gift async_pf_execute() a reference because all invocations of
async_pf_execute() will be forced to complete before the vCPU and its VM are destroyed/freed. And that in
turn fixes the module unloading bug as __fput() won't do module_put() on the last vCPU reference until the
vCPU has been freed, e.g. if closing the vCPU file also puts the last reference to the KVM module. Note
that kvm_check_async_pf_completion() may also take the work item off the completion queue and so also
needs to flush the work queue, as the work will not be seen by kvm_clear_async_pf_completion_queue().
Waiting on the workqueue could theoretically delay a vCPU due to waiting for the work to complete, but
that's a very, very small chance, and likely a very small delay. kvm_arch_async_page_present_queued()
unconditionally makes a new request, i.e. will effectively delay entering the guest, so the remaining work
is really just: trace_kvm_async_pf_completed(addr, cr2_or_gpa); __kvm_vcpu_wake_up(vcpu); mmput(mm); and
mmput() can't drop the last reference to the page tables if the vCPU is still alive, i.e. the vCPU won't
get stuck tearing down page tables. Add a helper to do the flushing, specifically to deal with "wakeup
all" work items, as they aren't actually work items, i.e. are never placed in a workqueue. Trying to flush
a bogus workqueue entry rightly makes __flush_work() complain (kudos to whoever added that sanity check).
Note, commit 5f6de5cbebee ("KVM: Prevent module exit until al ---truncated--- (CVE-2024-26976)

Solution

Update the sys-kernel/csql-kernel-6_1 library and its related packages to version 18244.85.5 or later.

Plugin Details

Severity: High

ID: 450653

Version: Revision 1.2

Type: Local

Family: Google COS Security Checks

Published: 10/1/2026

Updated: 10/2/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.12

Vendor

Vendor Severity: HIGH

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2024-26976

CVSS v3

Risk Factor: High

Base Score: 7

Temporal Score: 6.1

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

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

Vulnerability Information

Exploit Ease: No known exploits are available

Reference Information

CVE: CVE-2024-26976

Detections

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