FKIE_CVE-2026-64250

Vulnerability from fkie_nvd - Published: 2026-07-24 16:16 - Updated: 2026-07-30 15:00
Severity
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0833b2b84c2fc1387f8165f0cbf6a02d67f647a5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1fa22de588a65880d6fe54c38c87fffe7d519f60
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/262dadc619e69ebeb97affd334cd1078a9704e98
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/90e254f18b8c224460082329dd5c42fd30995c2f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a0269e928728f970c782319fee53d92d4ea4e512
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f2539c56c74691e7a88af6372ba2b48c06ed2fe4
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/loongarch/kernel/smp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "262dadc619e69ebeb97affd334cd1078a9704e98",
              "status": "affected",
              "version": "2dc79362302922cb18f35e262712b5e58de65442",
              "versionType": "git"
            },
            {
              "lessThan": "1fa22de588a65880d6fe54c38c87fffe7d519f60",
              "status": "affected",
              "version": "eef4f71b46a9929ac33e968538c9dd5d96a02460",
              "versionType": "git"
            },
            {
              "lessThan": "a0269e928728f970c782319fee53d92d4ea4e512",
              "status": "affected",
              "version": "684a78183c54c23e70d1cba320f7fc184604210b",
              "versionType": "git"
            },
            {
              "lessThan": "90e254f18b8c224460082329dd5c42fd30995c2f",
              "status": "affected",
              "version": "18c0456ea2615b1a743a6db739c74411c3b42bc6",
              "versionType": "git"
            },
            {
              "lessThan": "0833b2b84c2fc1387f8165f0cbf6a02d67f647a5",
              "status": "affected",
              "version": "91840be8f710370607f949a627e070896faeddb8",
              "versionType": "git"
            },
            {
              "lessThan": "f2539c56c74691e7a88af6372ba2b48c06ed2fe4",
              "status": "affected",
              "version": "91840be8f710370607f949a627e070896faeddb8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "81b582784518196eff1050212a046bc29d3a05dd",
              "versionType": "git"
            },
            {
              "lessThan": "6.1.178",
              "status": "affected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.145",
              "status": "affected",
              "version": "6.6.142",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.95",
              "status": "affected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThan": "6.18.38",
              "status": "affected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThan": "7.1",
              "status": "affected",
              "version": "7.0.11",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/loongarch/kernel/smp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "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."
    }
  ],
  "id": "CVE-2026-64250",
  "lastModified": "2026-07-30T15:00:27.343",
  "metrics": {},
  "published": "2026-07-24T16:16:54.577",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "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"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}



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