CVE-2026-64250 (GCVE-0-2026-64250)

Vulnerability from cvelistv5 – Published: 2026-07-24 15:31 – Updated: 2026-07-24 15:31
VLAI
Title
LoongArch: Report dying CPU to RCU in stop_this_cpu()
Summary
In the Linux kernel, the following vulnerability has been resolved: LoongArch: Report dying CPU to RCU in stop_this_cpu() This is a port of MIPS commit 9f3f3bdc6d9dac1 ("MIPS: smp: report dying CPU to RCU in stop_this_cpu()"). smp_send_stop() parks all secondary CPUs in stop_this_cpu(). And the function marks the CPU offline for the scheduler via set_cpu_online(false) but never informs RCU, so RCU keeps expecting a quiescent state from CPUs that are now spinning forever with interrupts disabled. As long as nothing waits for an RCU grace period after smp_send_stop() this is harmless, which is why it went unnoticed. However, since commit 91840be8f710370 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT"), irq_work_sync() calls synchronize_rcu() on architectures without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt() returns false. Any irq_work_sync() issued in the reboot/shutdown/halt path after smp_send_stop() then blocks on a grace period that can never complete, hanging the reboot: WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on ... rcu: INFO: rcu_sched detected stalls on CPUs/tasks: rcu: Offline CPU 1 blocking current GP. rcu: Offline CPU 2 blocking current GP. rcu: Offline CPU 3 blocking current GP. This issue needs some hacks to reproduce, and it was not noticed on LoongArch because arch_irq_work_has_interrupt() usually returns true. Call rcutree_report_cpu_dead() once interrupts are disabled, mirroring the generic CPU-hotplug offline path, so RCU stops waiting on the parked CPUs and grace periods can still complete. LoongArch shuts down all CPUs here without going through the CPU-hotplug mechanism, so this report is not otherwise issued.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 2dc79362302922cb18f35e262712b5e58de65442 , < 262dadc619e69ebeb97affd334cd1078a9704e98 (git)
Affected: eef4f71b46a9929ac33e968538c9dd5d96a02460 , < 1fa22de588a65880d6fe54c38c87fffe7d519f60 (git)
Affected: 684a78183c54c23e70d1cba320f7fc184604210b , < a0269e928728f970c782319fee53d92d4ea4e512 (git)
Affected: 18c0456ea2615b1a743a6db739c74411c3b42bc6 , < 90e254f18b8c224460082329dd5c42fd30995c2f (git)
Affected: 91840be8f710370607f949a627e070896faeddb8 , < 0833b2b84c2fc1387f8165f0cbf6a02d67f647a5 (git)
Affected: 91840be8f710370607f949a627e070896faeddb8 , < f2539c56c74691e7a88af6372ba2b48c06ed2fe4 (git)
Affected: 81b582784518196eff1050212a046bc29d3a05dd (git)
Affected: 6.1.175 , < 6.1.178 (semver)
Affected: 6.6.142 , < 6.6.145 (semver)
Affected: 6.12.92 , < 6.12.95 (semver)
Affected: 6.18.34 , < 6.18.38 (semver)
Affected: 7.0.11 , < 7.1 (semver)
Create a notification for this product.
Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.95 , ≤ 6.12.* (semver)
Unaffected: 6.18.38 , ≤ 6.18.* (semver)
Unaffected: 7.1.3 , ≤ 7.1.* (semver)
Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Report dying CPU to RCU in stop_this_cpu()\n\nThis is a port of MIPS commit 9f3f3bdc6d9dac1 (\"MIPS: smp: report dying\nCPU to RCU in stop_this_cpu()\"). smp_send_stop() parks all secondary\nCPUs in stop_this_cpu(). And the function marks the CPU offline for the\nscheduler via set_cpu_online(false) but never informs RCU, so RCU keeps\nexpecting a quiescent state from CPUs that are now spinning forever with\ninterrupts disabled.\n\nAs long as nothing waits for an RCU grace period after smp_send_stop()\nthis is harmless, which is why it went unnoticed. However, since commit\n91840be8f710370 (\"irq_work: Fix use-after-free in irq_work_single() on\nPREEMPT_RT\"), irq_work_sync() calls synchronize_rcu() on architectures\nwithout an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt()\nreturns false. Any irq_work_sync() issued in the reboot/shutdown/halt\npath after smp_send_stop() then blocks on a grace period that can never\ncomplete, hanging the reboot:\n\n  WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on\n  ...\n  rcu: INFO: rcu_sched detected stalls on CPUs/tasks:\n  rcu: Offline CPU 1 blocking current GP.\n  rcu: Offline CPU 2 blocking current GP.\n  rcu: Offline CPU 3 blocking current GP.\n\nThis issue needs some hacks to reproduce, and it was not noticed on\nLoongArch because arch_irq_work_has_interrupt() usually returns true.\n\nCall rcutree_report_cpu_dead() once interrupts are disabled, mirroring\nthe generic CPU-hotplug offline path, so RCU stops waiting on the parked\nCPUs and grace periods can still complete. LoongArch shuts down all CPUs\nhere without going through the CPU-hotplug mechanism, so this report is\nnot otherwise issued."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-24T15:31:17.021Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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        {
          "url": "https://git.kernel.org/stable/c/262dadc619e69ebeb97affd334cd1078a9704e98"
        },
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          "url": "https://git.kernel.org/stable/c/1fa22de588a65880d6fe54c38c87fffe7d519f60"
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          "url": "https://git.kernel.org/stable/c/0833b2b84c2fc1387f8165f0cbf6a02d67f647a5"
        },
        {
          "url": "https://git.kernel.org/stable/c/f2539c56c74691e7a88af6372ba2b48c06ed2fe4"
        }
      ],
      "title": "LoongArch: Report dying CPU to RCU in stop_this_cpu()",
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    }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64250",
    "datePublished": "2026-07-24T15:31:17.021Z",
    "dateReserved": "2026-07-19T15:36:31.773Z",
    "dateUpdated": "2026-07-24T15:31:17.021Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-64250",
      "date": "2026-08-01",
      "epss": "0.00161",
      "percentile": "0.0576"
    },
    "microsoft_vex": {
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      "cve": "CVE-2026-64250",
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      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "LoongArch: Report dying CPU to RCU in stop_this_cpu()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64250.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-64250\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-24T16:16:54.577\",\"lastModified\":\"2026-07-30T15:00:27.343\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nLoongArch: Report dying CPU to RCU in stop_this_cpu()\\n\\nThis is a port of MIPS commit 9f3f3bdc6d9dac1 (\\\"MIPS: smp: report dying\\nCPU to RCU in stop_this_cpu()\\\"). smp_send_stop() parks all secondary\\nCPUs in stop_this_cpu(). And the function marks the CPU offline for the\\nscheduler via set_cpu_online(false) but never informs RCU, so RCU keeps\\nexpecting a quiescent state from CPUs that are now spinning forever with\\ninterrupts disabled.\\n\\nAs long as nothing waits for an RCU grace period after smp_send_stop()\\nthis is harmless, which is why it went unnoticed. However, since commit\\n91840be8f710370 (\\\"irq_work: Fix use-after-free in irq_work_single() on\\nPREEMPT_RT\\\"), irq_work_sync() calls synchronize_rcu() on architectures\\nwithout an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt()\\nreturns false. Any irq_work_sync() issued in the reboot/shutdown/halt\\npath after smp_send_stop() then blocks on a grace period that can never\\ncomplete, hanging the reboot:\\n\\n  WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on\\n  ...\\n  rcu: INFO: rcu_sched detected stalls on CPUs/tasks:\\n  rcu: Offline CPU 1 blocking current GP.\\n  rcu: Offline CPU 2 blocking current GP.\\n  rcu: Offline CPU 3 blocking current GP.\\n\\nThis issue needs some hacks to reproduce, and it was not noticed on\\nLoongArch because arch_irq_work_has_interrupt() usually returns true.\\n\\nCall rcutree_report_cpu_dead() once interrupts are disabled, mirroring\\nthe generic CPU-hotplug offline path, so RCU stops waiting on the parked\\nCPUs and grace periods can still complete. LoongArch shuts down all CPUs\\nhere without going through the CPU-hotplug mechanism, so this report is\\nnot otherwise issued.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"arch/loongarch/kernel/smp.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2dc79362302922cb18f35e262712b5e58de65442\",\"lessThan\":\"262dadc619e69ebeb97affd334cd1078a9704e98\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"eef4f71b46a9929ac33e968538c9dd5d96a02460\",\"lessThan\":\"1fa22de588a65880d6fe54c38c87fffe7d519f60\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"684a78183c54c23e70d1cba320f7fc184604210b\",\"lessThan\":\"a0269e928728f970c782319fee53d92d4ea4e512\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"18c0456ea2615b1a743a6db739c74411c3b42bc6\",\"lessThan\":\"90e254f18b8c224460082329dd5c42fd30995c2f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"91840be8f710370607f949a627e070896faeddb8\",\"lessThan\":\"0833b2b84c2fc1387f8165f0cbf6a02d67f647a5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"91840be8f710370607f949a627e070896faeddb8\",\"lessThan\":\"f2539c56c74691e7a88af6372ba2b48c06ed2fe4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"81b582784518196eff1050212a046bc29d3a05dd\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"6.1.175\",\"lessThan\":\"6.1.178\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.6.142\",\"lessThan\":\"6.6.145\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.12.92\",\"lessThan\":\"6.12.95\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.18.34\",\"lessThan\":\"6.18.38\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"7.0.11\",\"lessThan\":\"7.1\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"arch/loongarch/kernel/smp.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"7.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.178\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.145\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.95\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.38\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.3\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0833b2b84c2fc1387f8165f0cbf6a02d67f647a5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/1fa22de588a65880d6fe54c38c87fffe7d519f60\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/262dadc619e69ebeb97affd334cd1078a9704e98\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/90e254f18b8c224460082329dd5c42fd30995c2f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a0269e928728f970c782319fee53d92d4ea4e512\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f2539c56c74691e7a88af6372ba2b48c06ed2fe4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-07-28T09:42:35+00:00",
      "cve": "CVE-2026-64250",
      "id": "CVE-2026-64250",
      "initial_release_date": "2026-07-24T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: LoongArch: Report dying CPU to RCU in stop_this_cpu()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64250.json",
      "version": "3"
    }
  }
}



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