FKIE_CVE-2026-64214
Vulnerability from fkie_nvd - Published: 2026-07-24 16:16 - Updated: 2026-08-11 17:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
powerpc/time: Remove redundant preempt_disable|enable() calls from arch_irq_work_raise()
A kernel panic is observed when handling machine check exceptions from
real mode.
BUG: Unable to handle kernel data access on read at 0xc00000006be21300
Oops: Kernel access of bad area, sig: 11 [#1]
MSR: 8000000000001003 <SF,ME,RI,LE> CR: 88222248 XER: 00000005
CFAR: c00000000003ffc4 DAR: c00000006be21300 DSISR: 40000000 IRQMASK: 0
NIP [c000000000029e40] arch_irq_work_raise+0x10/0x70
LR [c00000000003ffc8] machine_check_queue_event+0xa8/0x150
Call Trace:
[c0000000179d3c70] [c00000000003ff64] machine_check_queue_event+0x44/0x150
[c0000000179d3d30] [c0000000000084e0] machine_check_early_common+0x1f0/0x2c0
The crash occurs because arch_irq_work_raise() calls preempt_disable()
from machine check exception (MCE) handlers running in real mode. In
this context, accessing the preempt_count can fault, leading to the panic.
The preempt_disable()/preempt_enable() pair in arch_irq_work_raise()
was originally added by commit 0fe1ac48bef0 ("powerpc/perf_event: Fix
oops due to perf_event_do_pending call") to avoid races while raising
irq work from exception context.
Later, commit 471ba0e686cb ("irq_work: Do not raise an IPI when
queueing work on the local CPU") added preemption protection in
irq_work_queue() path, while commit 20b876918c06 ("irq_work: Use per
cpu atomics instead of regular atomics") added equivalent
protection in irq_work_queue_on() before reaching arch_irq_work_raise():
irq_work_queue() / irq_work_queue_on()
-> preempt_disable()
-> __irq_work_queue_local()
-> irq_work_raise()
-> arch_irq_work_raise()
As a result, callers other than mce_irq_work_raise() already execute
with preemption disabled, making the additional
preempt_disable()/preempt_enable() pair in arch_irq_work_raise()
redundant.
The arch_irq_work_raise() function executes in NMI context when called
from MCE handler. Hence we will not be preempted or scheduled out since
we are in NMI context with MSR[EE]=0. Therefore, it is safe to remove
the preempt_disable()/preempt_enable() calls from here.
Remove it to avoid accessing preempt_count from real mode context.
[Maddy: Fixed the commit title]
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 7.1 | |
| linux | linux_kernel | 7.1 | |
| linux | linux_kernel | 7.1 |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/powerpc/kernel/time.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "51860e423592893cd7bfa7287d99a3aff4dc3a9d",
"status": "affected",
"version": "cc15ff3275694fedc33cd3d53212a43eec7aa0bc",
"versionType": "git"
},
{
"lessThan": "a09d07ac45e283c9861a9ceea06f56d0ba851d22",
"status": "affected",
"version": "cc15ff3275694fedc33cd3d53212a43eec7aa0bc",
"versionType": "git"
},
{
"lessThan": "72d8d1c36452a4d3ee134b1da48de7518c1329f9",
"status": "affected",
"version": "cc15ff3275694fedc33cd3d53212a43eec7aa0bc",
"versionType": "git"
},
{
"lessThan": "6dcd072a5ae3aed336e4a67a7d4cc5205b240065",
"status": "affected",
"version": "cc15ff3275694fedc33cd3d53212a43eec7aa0bc",
"versionType": "git"
},
{
"lessThan": "8079acc5ee5235a627e4586d4f42082a9000ea64",
"status": "affected",
"version": "cc15ff3275694fedc33cd3d53212a43eec7aa0bc",
"versionType": "git"
},
{
"lessThan": "31467b23823ffec1f6fff407f8e3ca9af8b7491a",
"status": "affected",
"version": "cc15ff3275694fedc33cd3d53212a43eec7aa0bc",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"arch/powerpc/kernel/time.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.18"
},
{
"lessThan": "5.18",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.175",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.142",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.92",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.34",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.0.*",
"status": "unaffected",
"version": "7.0.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "FE99B3A9-CC61-4329-91B2-DC8483A7D1CF",
"versionEndExcluding": "6.1.175",
"versionStartIncluding": "5.18",
"vulnerable": true
},
{
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"versionEndExcluding": "6.6.142",
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},
{
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"versionEndExcluding": "6.12.92",
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},
{
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{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*",
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{
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{
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/time: Remove redundant preempt_disable|enable() calls from arch_irq_work_raise()\n\nA kernel panic is observed when handling machine check exceptions from\nreal mode.\n\n BUG: Unable to handle kernel data access on read at 0xc00000006be21300\n Oops: Kernel access of bad area, sig: 11 [#1]\n MSR: 8000000000001003 \u003cSF,ME,RI,LE\u003e CR: 88222248 XER: 00000005\n CFAR: c00000000003ffc4 DAR: c00000006be21300 DSISR: 40000000 IRQMASK: 0\n NIP [c000000000029e40] arch_irq_work_raise+0x10/0x70\n LR [c00000000003ffc8] machine_check_queue_event+0xa8/0x150\n Call Trace:\n [c0000000179d3c70] [c00000000003ff64] machine_check_queue_event+0x44/0x150\n [c0000000179d3d30] [c0000000000084e0] machine_check_early_common+0x1f0/0x2c0\n\nThe crash occurs because arch_irq_work_raise() calls preempt_disable()\nfrom machine check exception (MCE) handlers running in real mode. In\nthis context, accessing the preempt_count can fault, leading to the panic.\n\nThe preempt_disable()/preempt_enable() pair in arch_irq_work_raise()\nwas originally added by commit 0fe1ac48bef0 (\"powerpc/perf_event: Fix\noops due to perf_event_do_pending call\") to avoid races while raising\nirq work from exception context.\n\nLater, commit 471ba0e686cb (\"irq_work: Do not raise an IPI when\nqueueing work on the local CPU\") added preemption protection in\nirq_work_queue() path, while commit 20b876918c06 (\"irq_work: Use per\ncpu atomics instead of regular atomics\") added equivalent\nprotection in irq_work_queue_on() before reaching arch_irq_work_raise():\n\n irq_work_queue() / irq_work_queue_on()\n -\u003e preempt_disable()\n -\u003e __irq_work_queue_local()\n -\u003e irq_work_raise()\n -\u003e arch_irq_work_raise()\n\nAs a result, callers other than mce_irq_work_raise() already execute\nwith preemption disabled, making the additional\npreempt_disable()/preempt_enable() pair in arch_irq_work_raise()\nredundant.\n\nThe arch_irq_work_raise() function executes in NMI context when called\nfrom MCE handler. Hence we will not be preempted or scheduled out since\nwe are in NMI context with MSR[EE]=0. Therefore, it is safe to remove\nthe preempt_disable()/preempt_enable() calls from here.\n\nRemove it to avoid accessing preempt_count from real mode context.\n\n[Maddy: Fixed the commit title]"
}
],
"id": "CVE-2026-64214",
"lastModified": "2026-08-11T17:19:15.970",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2026-07-24T16:16:49.053",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/31467b23823ffec1f6fff407f8e3ca9af8b7491a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/51860e423592893cd7bfa7287d99a3aff4dc3a9d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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],
"url": "https://git.kernel.org/stable/c/6dcd072a5ae3aed336e4a67a7d4cc5205b240065"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/72d8d1c36452a4d3ee134b1da48de7518c1329f9"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/8079acc5ee5235a627e4586d4f42082a9000ea64"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/a09d07ac45e283c9861a9ceea06f56d0ba851d22"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-476"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
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- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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