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Fencer Vulns
medium 5.5

CVE-2022-50118 json

powerpc/perf: Optimize clearing the pending PMI and remove WARN_ON for PMI check in power_pmu_disable

published 2025-06-18 16 mo ago modified 2026-11-05 3 d ago also EUVD-2022-55384

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

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---

Patch / fix

  • Linux Linux 5.10.137, 5.15.61, 5.17, 5.18.18, 5.19.2, 6.0
  • linux Debian 14, Debian 13, Debian 12 6.0.2-1

debian advisories DEBIAN-CVE-2022-50118

  • linux Ubuntu 22.04 LTS 5.15.0-53.59
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1023.27
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1022.29
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1020.25
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1018.21
  • linux-kvm Ubuntu 22.04 LTS 5.15.0-1021.26
  • linux-azure Ubuntu 22.04 LTS 5.15.0-1023.29
  • linux-gkeop Ubuntu 22.04 LTS 5.15.0-1008.12

ubuntu advisories UBUNTU-CVE-2022-50118

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-64kb SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS, SLE High Performance Computing 15 SP4-ESPOS 5.14.21-150400.24.170.2
  • kernel-syms SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +3 more 5.14.21-150400.24.170.1
  • kernel-source SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +3 more 5.14.21-150400.24.170.1
  • kernel-default SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +6 more 5.14.21-150400.24.170.2
  • kernel-zfcpdump SLES 15 SP4-LTSS, Manager Server 4.3 5.14.21-150400.24.170.2
  • kernel-obs-build SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.14.21-150400.24.170.2
  • kernel-default-base SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +5 more 5.14.21-150400.24.170.2.150400.24.86.2
  • kernel-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.124.1

suse advisories SUSE-SU-2025:02537-1SUSE-SU-2025:02322-1SUSE-SU-2025:02321-1SUSE-SU-2025:02320-1SUSE-SU-2025:02308-1SUSE-SU-2025:02264-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2022-50118 updated cvss 4.1

kernel: powerpc/perf: Optimize clearing the pending PMI and remove WARN_ON for PMI check in power_pmu_disable

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 d ago

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

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