Detections
Analytics
Unity Linux 20.1060e / 20.1070e Security Update: kernel (UTSA-2025-992472)
medium Nessus Plugin ID 280452
Synopsis
The Unity Linux host is missing one or more security updates.Description
The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2025-992472 advisory.In the Linux kernel, the following vulnerability has been resolved:
powerpc/perf: Optimize clearing the pending PMI and remove WARN_ON for PMI check in power_pmu_disable
commit 2c9ac51b850d (powerpc/perf: Fix PMU callbacks to clear pending PMI before resetting an overflown PMC) added a new function pmi_irq_pending in hw_irq.h. This function is to check if there is a PMI marked as pending in Paca (PACA_IRQ_PMI).This is used in power_pmu_disable in a WARN_ON. The intention here is to provide a warning if there is PMI pending, but no counter is found overflown.
During some of the perf runs, below warning is hit:
WARNING: CPU: 36 PID: 0 at arch/powerpc/perf/core-book3s.c:1332 power_pmu_disable+0x25c/0x2c0 Modules linked in:
-----
NIP [c000000000141c3c] power_pmu_disable+0x25c/0x2c0 LR [c000000000141c8c] power_pmu_disable+0x2ac/0x2c0 Call Trace:
[c000000baffcfb90] [c000000000141c8c] power_pmu_disable+0x2ac/0x2c0 (unreliable) [c000000baffcfc10] [c0000000003e2f8c] perf_pmu_disable+0x4c/0x60 [c000000baffcfc30] [c0000000003e3344] group_sched_out.part.124+0x44/0x100 [c000000baffcfc80] [c0000000003e353c] __perf_event_disable+0x13c/0x240 [c000000baffcfcd0] [c0000000003dd334] event_function+0xc4/0x140 [c000000baffcfd20] [c0000000003d855c] remote_function+0x7c/0xa0 [c000000baffcfd50] [c00000000026c394] flush_smp_call_function_queue+0xd4/0x300 [c000000baffcfde0] [c000000000065b24] smp_ipi_demux_relaxed+0xa4/0x100 [c000000baffcfe20] [c0000000000cb2b0] xive_muxed_ipi_action+0x20/0x40 [c000000baffcfe40] [c000000000207c3c] __handle_irq_event_percpu+0x8c/0x250 [c000000baffcfee0] [c000000000207e2c] handle_irq_event_percpu+0x2c/0xa0 [c000000baffcff10] [c000000000210a04] handle_percpu_irq+0x84/0xc0 [c000000baffcff40] [c000000000205f14] generic_handle_irq+0x54/0x80 [c000000baffcff60] [c000000000015740] __do_irq+0x90/0x1d0 [c000000baffcff90] [c000000000016990] __do_IRQ+0xc0/0x140 [c0000009732f3940] [c000000bafceaca8] 0xc000000bafceaca8 [c0000009732f39d0] [c000000000016b78] do_IRQ+0x168/0x1c0 [c0000009732f3a00] [c0000000000090c8] hardware_interrupt_common_virt+0x218/0x220
This means that there is no PMC overflown among the active events in the PMU, but there is a PMU pending in Paca. The function any_pmc_overflown checks the PMCs on active events in cpuhw->n_events. Code snippet:
<<>> if (any_pmc_overflown(cpuhw)) clear_pmi_irq_pending();
else WARN_ON(pmi_irq_pending());
<<>>
Here the PMC overflown is not from active event. Example: When we do perf record, default cycles and instructions will be running on PMC6 and PMC5 respectively. It could happen that overflowed event is currently not active and pending PMI is for the inactive event. Debug logs from trace_printk:
<<>> any_pmc_overflown: idx is 5: pmc value is 0xd9a power_pmu_disable: PMC1: 0x0, PMC2: 0x0, PMC3: 0x0, PMC4: 0x0, PMC5: 0xd9a, PMC6: 0x80002011 <<>>
Here active PMC (from idx) is PMC5 , but overflown PMC is PMC6(0x80002011).
When we handle PMI interrupt for such cases, if the PMC overflown is from inactive event, it will be ignored. Reference commit:
commit bc09c219b2e6 (powerpc/perf: Fix finding overflowed PMC in interrupt)
Patch addresses two changes:
1) Fix 1 : Removal of warning ( WARN_ON(pmi_irq_pending()); ) We were printing warning if no PMC is found overflown among active PMU events, but PMI pending in PACA. But this could happen in cases where PMC overflown is not in active PMC. An inactive event could have caused the overflow. Hence the warning is not needed. To know pending PMI is from an inactive event, we need to loop through all PMC's which will cause more SPR reads via mfspr and increase in context switch. Also in existing function: perf_event_interrupt, already we ignore PMI's overflown when it is from an inactive PMC.
2) Fix 2: optimization in clearing pending PMI.
Currently we check for any active PMC overflown before clearing PMI pending in Paca. This is causing additional SP
---truncated---
Tenable has extracted the preceding description block directly from the Unity Linux security advisory.
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
Solution
Update the affected kernel package.See Also
http://www.nessus.org/u?3836acac
Plugin Details
Severity: Medium
ID: 280452
File Name: unity_linux_UTSA-2025-992472.nasl
Version: 1.1
Type: local
Published: 12/30/2025
Updated: 12/30/2025
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 4.4
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-2022-50118
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
Required KB Items: Host/local_checks_enabled, Host/UOS-Server/release, Host/UOS-Server/rpm-list, Host/cpu
Exploit Ease: No known exploits are available
Patch Publication Date: 12/30/2025
Vulnerability Publication Date: 6/18/2025
Reference Information
CVE: CVE-2022-50118