Description
In the Linux kernel, the following vulnerability has been resolved:

powerpc: Avoid nmi_enter/nmi_exit in real mode interrupt.

nmi_enter()/nmi_exit() touches per cpu variables which can lead to kernel
crash when invoked during real mode interrupt handling (e.g. early HMI/MCE
interrupt handler) if percpu allocation comes from vmalloc area.

Early HMI/MCE handlers are called through DEFINE_INTERRUPT_HANDLER_NMI()
wrapper which invokes nmi_enter/nmi_exit calls. We don't see any issue when
percpu allocation is from the embedded first chunk. However with
CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK enabled there are chances where percpu
allocation can come from the vmalloc area.

With kernel command line "percpu_alloc=page" we can force percpu allocation
to come from vmalloc area and can see kernel crash in machine_check_early:

[ 1.215714] NIP [c000000000e49eb4] rcu_nmi_enter+0x24/0x110
[ 1.215717] LR [c0000000000461a0] machine_check_early+0xf0/0x2c0
[ 1.215719] --- interrupt: 200
[ 1.215720] [c000000fffd73180] [0000000000000000] 0x0 (unreliable)
[ 1.215722] [c000000fffd731b0] [0000000000000000] 0x0
[ 1.215724] [c000000fffd73210] [c000000000008364] machine_check_early_common+0x134/0x1f8

Fix this by avoiding use of nmi_enter()/nmi_exit() in real mode if percpu
first chunk is not embedded.
Published: 2024-07-30
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4008-1 linux-6.1 security update
Ubuntu USN Ubuntu USN USN-7089-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-5 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-6 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-7 Linux kernel (Low Latency) vulnerabilities
Ubuntu USN Ubuntu USN USN-7090-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7095-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7100-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7100-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7123-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7144-1 Linux kernel (Intel IoTG) vulnerabilities
Ubuntu USN Ubuntu USN USN-7156-1 Linux kernel (GKE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7194-1 Linux kernel (Azure) vulnerabilities
History

Mon, 03 Nov 2025 22:30:00 +0000

Type Values Removed Values Added
References

Mon, 06 Oct 2025 17:15:00 +0000

Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Tue, 05 Nov 2024 10:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 25 Oct 2024 15:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-827
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'}


Thu, 12 Sep 2024 08:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 11 Sep 2024 13:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 19 Aug 2024 04:45:00 +0000


Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T20:27:29.815Z

Reserved: 2024-07-29T15:50:41.179Z

Link: CVE-2024-42126

cve-icon Vulnrichment

Updated: 2025-11-03T22:01:57.533Z

cve-icon NVD

Status : Modified

Published: 2024-07-30T08:15:04.743

Modified: 2025-11-03T22:17:40.750

Link: CVE-2024-42126

cve-icon Redhat

Severity : Low

Publid Date: 2024-07-30T00:00:00Z

Links: CVE-2024-42126 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-07-13T11:15:05Z

Weaknesses