Vulnerability-Lookup

GHSA-5QJX-3F5W-QJ49

Vulnerability from github – Published: 2026-07-24 18:31 – Updated: 2026-07-24 18:31

Details

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 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]

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64214"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-24T16:16:49Z",
    "severity": null
  },
  "details": "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": "GHSA-5qjx-3f5w-qj49",
  "modified": "2026-07-24T18:31:27Z",
  "published": "2026-07-24T18:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64214"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/31467b23823ffec1f6fff407f8e3ca9af8b7491a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/51860e423592893cd7bfa7287d99a3aff4dc3a9d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6dcd072a5ae3aed336e4a67a7d4cc5205b240065"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/72d8d1c36452a4d3ee134b1da48de7518c1329f9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8079acc5ee5235a627e4586d4f42082a9000ea64"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a09d07ac45e283c9861a9ceea06f56d0ba851d22"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64214 (GCVE-0-2026-64214)

Vulnerability from cvelistv5 – Published: 2026-07-24 15:23 – Updated: 2026-07-24 15:23

Title

powerpc/time: Remove redundant preempt_disable|enable() calls from arch_irq_work_raise()

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]

Severity

No CVSS data available.

Assigner

Linux

References

6 references

URL	Tags
https://git.kernel.org/stable/c/51860e423592893cd…
https://git.kernel.org/stable/c/a09d07ac45e283c98…
https://git.kernel.org/stable/c/72d8d1c36452a4d3e…
https://git.kernel.org/stable/c/6dcd072a5ae3aed33…
https://git.kernel.org/stable/c/8079acc5ee5235a62…
https://git.kernel.org/stable/c/31467b23823ffec1f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: cc15ff3275694fedc33cd3d53212a43eec7aa0bc , < 51860e423592893cd7bfa7287d99a3aff4dc3a9d (git) Affected: cc15ff3275694fedc33cd3d53212a43eec7aa0bc , < a09d07ac45e283c9861a9ceea06f56d0ba851d22 (git) Affected: cc15ff3275694fedc33cd3d53212a43eec7aa0bc , < 72d8d1c36452a4d3ee134b1da48de7518c1329f9 (git) Affected: cc15ff3275694fedc33cd3d53212a43eec7aa0bc , < 6dcd072a5ae3aed336e4a67a7d4cc5205b240065 (git) Affected: cc15ff3275694fedc33cd3d53212a43eec7aa0bc , < 8079acc5ee5235a627e4586d4f42082a9000ea64 (git) Affected: cc15ff3275694fedc33cd3d53212a43eec7aa0bc , < 31467b23823ffec1f6fff407f8e3ca9af8b7491a (git)
Linux	Linux	Affected: 5.18 Unaffected: 0 , < 5.18 (semver) Unaffected: 6.1.175 , ≤ 6.1.* (semver) Unaffected: 6.6.142 , ≤ 6.6.* (semver) Unaffected: 6.12.92 , ≤ 6.12.* (semver) Unaffected: 6.18.34 , ≤ 6.18.* (semver) Unaffected: 7.0.11 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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{
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        {
          "defaultStatus": "unaffected",
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          "programFiles": [
            "arch/powerpc/kernel/time.c"
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          "defaultStatus": "affected",
          "product": "Linux",
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          "versions": [
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              "version": "0",
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              "status": "unaffected",
              "version": "6.6.142",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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          "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]"
        }
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          "url": "https://git.kernel.org/stable/c/31467b23823ffec1f6fff407f8e3ca9af8b7491a"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64214",
    "datePublished": "2026-07-24T15:23:03.529Z",
    "dateReserved": "2026-07-19T15:36:31.770Z",
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}

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.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

GHSA-5QJX-3F5W-QJ49

CVE-2026-64214 (GCVE-0-2026-64214)

Tags

Sightings

Nomenclature