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.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4008-1 | linux-6.1 security update |
Ubuntu USN |
USN-7089-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7089-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7089-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7089-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7089-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7089-6 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7089-7 | Linux kernel (Low Latency) vulnerabilities |
Ubuntu USN |
USN-7090-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7095-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7100-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7100-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7123-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7144-1 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-7156-1 | Linux kernel (GKE) vulnerabilities |
Ubuntu USN |
USN-7194-1 | Linux kernel (Azure) vulnerabilities |
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
|
cvssV3_1
|
Tue, 05 Nov 2024 10:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Fri, 25 Oct 2024 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-827 | |
| Metrics |
cvssV3_1
|
cvssV3_1
|
Thu, 12 Sep 2024 08:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 11 Sep 2024 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Mon, 19 Aug 2024 04:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T20:27:29.815Z
Reserved: 2024-07-29T15:50:41.179Z
Link: CVE-2024-42126
Updated: 2025-11-03T22:01:57.533Z
Status : Modified
Published: 2024-07-30T08:15:04.743
Modified: 2025-11-03T22:17:40.750
Link: CVE-2024-42126
OpenCVE Enrichment
Updated: 2025-07-13T11:15:05Z
Debian DLA
Ubuntu USN