CVE-2021-47454 (GCVE-0-2021-47454)

Vulnerability from cvelistv5 – Published: 2024-05-22 06:19 – Updated: 2026-05-23 15:20
VLAI
Title
powerpc/smp: do not decrement idle task preempt count in CPU offline
Summary
In the Linux kernel, the following vulnerability has been resolved: powerpc/smp: do not decrement idle task preempt count in CPU offline With PREEMPT_COUNT=y, when a CPU is offlined and then onlined again, we get: BUG: scheduling while atomic: swapper/1/0/0x00000000 no locks held by swapper/1/0. CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.0-rc2+ #100 Call Trace: dump_stack_lvl+0xac/0x108 __schedule_bug+0xac/0xe0 __schedule+0xcf8/0x10d0 schedule_idle+0x3c/0x70 do_idle+0x2d8/0x4a0 cpu_startup_entry+0x38/0x40 start_secondary+0x2ec/0x3a0 start_secondary_prolog+0x10/0x14 This is because powerpc's arch_cpu_idle_dead() decrements the idle task's preempt count, for reasons explained in commit a7c2bb8279d2 ("powerpc: Re-enable preemption before cpu_die()"), specifically "start_secondary() expects a preempt_count() of 0." However, since commit 2c669ef6979c ("powerpc/preempt: Don't touch the idle task's preempt_count during hotplug") and commit f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled"), that justification no longer holds. The idle task isn't supposed to re-enable preemption, so remove the vestigial preempt_enable() from the CPU offline path. Tested with pseries and powernv in qemu, and pseries on PowerVM.
Severity
No CVSS data available.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-05-22 19:49 UTC
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7033 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bdf4d33e8342b90386156204e1da0cdfdb4bf146 , < 53770a411559cf7bc0906d1df319cc533d2f4f58 (git)
Affected: 2c669ef6979c370f98d4b876e54f19613c81e075 , < 3ea0b497a7a2fff6a4b7090310c9f52c91975934 (git)
Affected: 2c669ef6979c370f98d4b876e54f19613c81e075 , < 787252a10d9422f3058df9a4821f389e5326c440 (git)
Affected: 2b6148ef2bd6d8ddc76e7873114f7769b6aa25f0 (git)
Affected: 20a015e948b825afb47855de2efce7cae7c2608f (git)
Affected: 5.10.50 , < 5.10.76 (semver)
Affected: 5.12.17 , < 5.13 (semver)
Affected: 5.13.2 , < 5.14 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 5.14
Unaffected: 0 , < 5.14 (semver)
Unaffected: 5.10.76 , ≤ 5.10.* (semver)
Unaffected: 5.14.15 , ≤ 5.14.* (semver)
Unaffected: 5.15 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47454",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-22T19:49:10.356521Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-06-04T17:13:30.604Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:39:59.627Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/53770a411559cf7bc0906d1df319cc533d2f4f58"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/3ea0b497a7a2fff6a4b7090310c9f52c91975934"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/787252a10d9422f3058df9a4821f389e5326c440"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/kernel/smp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "53770a411559cf7bc0906d1df319cc533d2f4f58",
              "status": "affected",
              "version": "bdf4d33e8342b90386156204e1da0cdfdb4bf146",
              "versionType": "git"
            },
            {
              "lessThan": "3ea0b497a7a2fff6a4b7090310c9f52c91975934",
              "status": "affected",
              "version": "2c669ef6979c370f98d4b876e54f19613c81e075",
              "versionType": "git"
            },
            {
              "lessThan": "787252a10d9422f3058df9a4821f389e5326c440",
              "status": "affected",
              "version": "2c669ef6979c370f98d4b876e54f19613c81e075",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "2b6148ef2bd6d8ddc76e7873114f7769b6aa25f0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "20a015e948b825afb47855de2efce7cae7c2608f",
              "versionType": "git"
            },
            {
              "lessThan": "5.10.76",
              "status": "affected",
              "version": "5.10.50",
              "versionType": "semver"
            },
            {
              "lessThan": "5.13",
              "status": "affected",
              "version": "5.12.17",
              "versionType": "semver"
            },
            {
              "lessThan": "5.14",
              "status": "affected",
              "version": "5.13.2",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/kernel/smp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.14"
            },
            {
              "lessThan": "5.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.76",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.14.*",
              "status": "unaffected",
              "version": "5.14.15",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.15",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.76",
                  "versionStartIncluding": "5.10.50",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.14.15",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.12.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.13.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/smp: do not decrement idle task preempt count in CPU offline\n\nWith PREEMPT_COUNT=y, when a CPU is offlined and then onlined again, we\nget:\n\nBUG: scheduling while atomic: swapper/1/0/0x00000000\nno locks held by swapper/1/0.\nCPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.0-rc2+ #100\nCall Trace:\n dump_stack_lvl+0xac/0x108\n __schedule_bug+0xac/0xe0\n __schedule+0xcf8/0x10d0\n schedule_idle+0x3c/0x70\n do_idle+0x2d8/0x4a0\n cpu_startup_entry+0x38/0x40\n start_secondary+0x2ec/0x3a0\n start_secondary_prolog+0x10/0x14\n\nThis is because powerpc\u0027s arch_cpu_idle_dead() decrements the idle task\u0027s\npreempt count, for reasons explained in commit a7c2bb8279d2 (\"powerpc:\nRe-enable preemption before cpu_die()\"), specifically \"start_secondary()\nexpects a preempt_count() of 0.\"\n\nHowever, since commit 2c669ef6979c (\"powerpc/preempt: Don\u0027t touch the idle\ntask\u0027s preempt_count during hotplug\") and commit f1a0a376ca0c (\"sched/core:\nInitialize the idle task with preemption disabled\"), that justification no\nlonger holds.\n\nThe idle task isn\u0027t supposed to re-enable preemption, so remove the\nvestigial preempt_enable() from the CPU offline path.\n\nTested with pseries and powernv in qemu, and pseries on PowerVM."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-23T15:20:00.262Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/53770a411559cf7bc0906d1df319cc533d2f4f58"
        },
        {
          "url": "https://git.kernel.org/stable/c/3ea0b497a7a2fff6a4b7090310c9f52c91975934"
        },
        {
          "url": "https://git.kernel.org/stable/c/787252a10d9422f3058df9a4821f389e5326c440"
        }
      ],
      "title": "powerpc/smp: do not decrement idle task preempt count in CPU offline",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47454",
    "datePublished": "2024-05-22T06:19:44.040Z",
    "dateReserved": "2024-05-21T14:58:30.833Z",
    "dateUpdated": "2026-05-23T15:20:00.262Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-47454",
      "date": "2026-10-29",
      "epss": "0.00225",
      "percentile": "0.13201"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "arch/powerpc/kernel/smp.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "53770a411559cf7bc0906d1df319cc533d2f4f58",
                    "status": "affected",
                    "version": "bdf4d33e8342b90386156204e1da0cdfdb4bf146",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "3ea0b497a7a2fff6a4b7090310c9f52c91975934",
                    "status": "affected",
                    "version": "2c669ef6979c370f98d4b876e54f19613c81e075",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "787252a10d9422f3058df9a4821f389e5326c440",
                    "status": "affected",
                    "version": "2c669ef6979c370f98d4b876e54f19613c81e075",
                    "versionType": "git"
                  },
                  {
                    "status": "affected",
                    "version": "2b6148ef2bd6d8ddc76e7873114f7769b6aa25f0",
                    "versionType": "git"
                  },
                  {
                    "status": "affected",
                    "version": "20a015e948b825afb47855de2efce7cae7c2608f",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5.10.76",
                    "status": "affected",
                    "version": "5.10.50",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "5.13",
                    "status": "affected",
                    "version": "5.12.17",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "5.14",
                    "status": "affected",
                    "version": "5.13.2",
                    "versionType": "semver"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "arch/powerpc/kernel/smp.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.14"
                  },
                  {
                    "lessThan": "5.14",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.10.*",
                    "status": "unaffected",
                    "version": "5.10.76",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.14.*",
                    "status": "unaffected",
                    "version": "5.14.15",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "5.15",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "54D73BB5-05A6-4980-BAB3-2AAAEFB143AC",
                    "versionEndExcluding": "5.10.76",
                    "versionStartIncluding": "5.10.50",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "CDB1D52E-21AB-4ECE-9119-6594F8FF3B3A",
                    "versionEndExcluding": "5.13",
                    "versionStartIncluding": "5.12.17",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "F839A199-75DE-4660-A33E-5921B73B1FF6",
                    "versionEndExcluding": "5.14.15",
                    "versionStartIncluding": "5.13.2",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "E46C74C6-B76B-4C94-A6A4-FD2FFF62D644",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "60134C3A-06E4-48C1-B04F-2903732A4E56",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "0460DA88-8FE1-46A2-9DDA-1F1ABA552E71",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*",
                    "matchCriteriaId": "AF55383D-4DF2-45DC-93F7-571F4F978EAB",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:*",
                    "matchCriteriaId": "9E9481B2-8AA6-4CBD-B5D3-C10F51FF6D01",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.15:rc6:*:*:*:*:*:*",
                    "matchCriteriaId": "EBD45831-4B79-42BC-ABC0-86870F0DEA89",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/smp: do not decrement idle task preempt count in CPU offline\n\nWith PREEMPT_COUNT=y, when a CPU is offlined and then onlined again, we\nget:\n\nBUG: scheduling while atomic: swapper/1/0/0x00000000\nno locks held by swapper/1/0.\nCPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.0-rc2+ #100\nCall Trace:\n dump_stack_lvl+0xac/0x108\n __schedule_bug+0xac/0xe0\n __schedule+0xcf8/0x10d0\n schedule_idle+0x3c/0x70\n do_idle+0x2d8/0x4a0\n cpu_startup_entry+0x38/0x40\n start_secondary+0x2ec/0x3a0\n start_secondary_prolog+0x10/0x14\n\nThis is because powerpc\u0027s arch_cpu_idle_dead() decrements the idle task\u0027s\npreempt count, for reasons explained in commit a7c2bb8279d2 (\"powerpc:\nRe-enable preemption before cpu_die()\"), specifically \"start_secondary()\nexpects a preempt_count() of 0.\"\n\nHowever, since commit 2c669ef6979c (\"powerpc/preempt: Don\u0027t touch the idle\ntask\u0027s preempt_count during hotplug\") and commit f1a0a376ca0c (\"sched/core:\nInitialize the idle task with preemption disabled\"), that justification no\nlonger holds.\n\nThe idle task isn\u0027t supposed to re-enable preemption, so remove the\nvestigial preempt_enable() from the CPU offline path.\n\nTested with pseries and powernv in qemu, and pseries on PowerVM."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: powerpc/smp: no disminuye el recuento de prioridad de tareas inactivas en la CPU fuera de l\u00ednea Con PREEMPT_COUNT=y, cuando una CPU est\u00e1 fuera de l\u00ednea y luego vuelve a estar en l\u00ednea, obtenemos: ERROR: programaci\u00f3n mientras es at\u00f3mica: swapper/1/0/0x00000000 no hay bloqueos retenidos por swapper/1/0. CPU: 1 PID: 0 Comunicaciones: swapper/1 No contaminado 5.15.0-rc2+ #100 Seguimiento de llamadas: dump_stack_lvl+0xac/0x108 __schedule_bug+0xac/0xe0 __schedule+0xcf8/0x10d0 Schedule_idle+0x3c/0x70 do_idle+0x2d8/0x4a0 entrada_arriba+ 0x38/0x40 start_secondary+0x2ec/0x3a0 start_secondary_prolog+0x10/0x14 Esto se debe a que arch_cpu_idle_dead() de powerpc disminuye el recuento de apropiaci\u00f3n de tareas inactivas, por razones explicadas en el commit a7c2bb8279d2 (\"powerpc: volver a habilitar la apropiaci\u00f3n antes de cpu_die()\"), espec\u00edficamente \" start_secondary() espera un preempt_count() de 0.\" Sin embargo, desde el commit 2c669ef6979c (\"powerpc/preempt: no toque el preempt_count de la tarea inactiva durante la conexi\u00f3n en caliente\") y el commit f1a0a376ca0c (\"sched/core: inicialice la tarea inactiva con la preferencia deshabilitada\"), esa justificaci\u00f3n ya no se cumple. No se supone que la tarea inactiva vuelva a habilitar la preferencia, por lo tanto, elimine el preempt_enable() residual de la ruta fuera de l\u00ednea de la CPU. Probado con pseries y powernv en qemu y pseries en PowerVM."
          }
        ],
        "id": "CVE-2021-47454",
        "lastModified": "2026-06-17T04:17:30.660",
        "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"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2021-47454",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-22T19:49:10.356521Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2024-05-22T07:15:10.453",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/3ea0b497a7a2fff6a4b7090310c9f52c91975934"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/53770a411559cf7bc0906d1df319cc533d2f4f58"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/787252a10d9422f3058df9a4821f389e5326c440"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/3ea0b497a7a2fff6a4b7090310c9f52c91975934"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/53770a411559cf7bc0906d1df319cc533d2f4f58"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/787252a10d9422f3058df9a4821f389e5326c440"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-noinfo"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-28T07:50:03+00:00",
      "cve": "CVE-2021-47454",
      "id": "CVE-2021-47454",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:fixed": "280",
      "product_status:known_affected": "64",
      "product_status:known_not_affected": "56",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: powerpc/smp: do not decrement idle task preempt count in CPU offline",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47454.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2024-08-04T05:39:59.627Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/53770a411559cf7bc0906d1df319cc533d2f4f58"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/3ea0b497a7a2fff6a4b7090310c9f52c91975934"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/787252a10d9422f3058df9a4821f389e5326c440"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2021-47454",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2024-05-22T19:49:10.356521Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2024-05-22T19:49:14.875Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "arch/powerpc/kernel/smp.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "53770a411559cf7bc0906d1df319cc533d2f4f58",
                  "status": "affected",
                  "version": "bdf4d33e8342b90386156204e1da0cdfdb4bf146",
                  "versionType": "git"
                },
                {
                  "lessThan": "3ea0b497a7a2fff6a4b7090310c9f52c91975934",
                  "status": "affected",
                  "version": "2c669ef6979c370f98d4b876e54f19613c81e075",
                  "versionType": "git"
                },
                {
                  "lessThan": "787252a10d9422f3058df9a4821f389e5326c440",
                  "status": "affected",
                  "version": "2c669ef6979c370f98d4b876e54f19613c81e075",
                  "versionType": "git"
                },
                {
                  "status": "affected",
                  "version": "2b6148ef2bd6d8ddc76e7873114f7769b6aa25f0",
                  "versionType": "git"
                },
                {
                  "status": "affected",
                  "version": "20a015e948b825afb47855de2efce7cae7c2608f",
                  "versionType": "git"
                },
                {
                  "lessThan": "5.10.76",
                  "status": "affected",
                  "version": "5.10.50",
                  "versionType": "semver"
                },
                {
                  "lessThan": "5.13",
                  "status": "affected",
                  "version": "5.12.17",
                  "versionType": "semver"
                },
                {
                  "lessThan": "5.14",
                  "status": "affected",
                  "version": "5.13.2",
                  "versionType": "semver"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "arch/powerpc/kernel/smp.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "5.14"
                },
                {
                  "lessThan": "5.14",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.10.*",
                  "status": "unaffected",
                  "version": "5.10.76",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.14.*",
                  "status": "unaffected",
                  "version": "5.14.15",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "5.15",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.10.76",
                      "versionStartIncluding": "5.10.50",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.14.15",
                      "versionStartIncluding": "5.14",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.15",
                      "versionStartIncluding": "5.14",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionStartIncluding": "5.12.17",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionStartIncluding": "5.13.2",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/smp: do not decrement idle task preempt count in CPU offline\n\nWith PREEMPT_COUNT=y, when a CPU is offlined and then onlined again, we\nget:\n\nBUG: scheduling while atomic: swapper/1/0/0x00000000\nno locks held by swapper/1/0.\nCPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.0-rc2+ #100\nCall Trace:\n dump_stack_lvl+0xac/0x108\n __schedule_bug+0xac/0xe0\n __schedule+0xcf8/0x10d0\n schedule_idle+0x3c/0x70\n do_idle+0x2d8/0x4a0\n cpu_startup_entry+0x38/0x40\n start_secondary+0x2ec/0x3a0\n start_secondary_prolog+0x10/0x14\n\nThis is because powerpc\u0027s arch_cpu_idle_dead() decrements the idle task\u0027s\npreempt count, for reasons explained in commit a7c2bb8279d2 (\"powerpc:\nRe-enable preemption before cpu_die()\"), specifically \"start_secondary()\nexpects a preempt_count() of 0.\"\n\nHowever, since commit 2c669ef6979c (\"powerpc/preempt: Don\u0027t touch the idle\ntask\u0027s preempt_count during hotplug\") and commit f1a0a376ca0c (\"sched/core:\nInitialize the idle task with preemption disabled\"), that justification no\nlonger holds.\n\nThe idle task isn\u0027t supposed to re-enable preemption, so remove the\nvestigial preempt_enable() from the CPU offline path.\n\nTested with pseries and powernv in qemu, and pseries on PowerVM."
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-05-23T15:20:00.262Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/53770a411559cf7bc0906d1df319cc533d2f4f58"
            },
            {
              "url": "https://git.kernel.org/stable/c/3ea0b497a7a2fff6a4b7090310c9f52c91975934"
            },
            {
              "url": "https://git.kernel.org/stable/c/787252a10d9422f3058df9a4821f389e5326c440"
            }
          ],
          "title": "powerpc/smp: do not decrement idle task preempt count in CPU offline",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2021-47454",
        "datePublished": "2024-05-22T06:19:44.040Z",
        "dateReserved": "2024-05-21T14:58:30.833Z",
        "dateUpdated": "2026-05-23T15:20:00.262Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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.
  • 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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.