workqueue: Fix selection of wake_cpu in kick_pool()

{
  "id": "b222a31c07bad0229f205a881fb31508f66bf8979ca84c6f5f1360ee89c6abb9",
  "url": "https://osv.dev/vulnerability/CVE-2024-36888",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "workqueue: Fix selection of wake_cpu in kick_pool()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix selection of wake_cpu in kick_pool() With cpu_possible_mask=0-63 and cpu_online_mask=0-7 the following kernel oops was observed: smp: Bringing up secondary CPUs ... smp: Brought up 1 node, 8 CPUs Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000803 [..] Call Trace: arch_vcpu_is_preempted+0x12/0x80 select_idle_sibling+0x42/0x560 select_task_rq_fair+0x29a/0x3b0 try_to_wake_up+0x38e/0x6e0 kick_pool+0xa4/0x198 __queue_work.part.0+0x2bc/0x3a8 call_timer_fn+0x36/0x160 __run_timers+0x1e2/0x328 __run_timer_base+0x5a/0x88 run_timer_softirq+0x40/0x78 __do_softirq+0x118/0x388 irq_exit_rcu+0xc0/0xd8 do_ext_irq+0xae/0x168 ext_int_handler+0xbe/0xf0 psw_idle_exit+0x0/0xc default_idle_call+0x3c/0x110 do_idle+0xd4/0x158 cpu_startup_entry+0x40/0x48 rest_init+0xc6/0xc8 start_kernel+0x3c4/0x5e0 startup_continue+0x3c/0x50 The crash is caused by calling arch_vcpu_is_preempted() for an offline CPU. To avoid this, select the cpu with cpumask_any_and_distribute() to mask __pod_cpumask with cpu_online_mask. In case no cpu is left in the pool, skip the assignment. tj: This doesn't fully fix the bug as CPUs can still go down between picking the target CPU and the wake call. Fixing that likely requires adding cpu_online() test to either the sched or s390 arch code. However, regardless of how that is fixed, workqueue shouldn't be picking a CPU w",
    "evidence": "osv:CVE-2024-36888",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.31",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.8.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2024-36888",
      "aliases": [
        "CVE-2024-36888"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "8639ecebc9b1796d7074751a350462f5e1c61cd4"
                },
                {
                  "fixed": "c57824d4fe07c2131f8c48687cbd5ee2be60c767"
                },
                {
                  "fixed": "6d559e70b3eb6623935cbe7f94c1912c1099777b"
                },
                {
                  "fixed": "57a01eafdcf78f6da34fad9ff075ed5dfdd9f420"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-36888.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.6.0"
                },
                {
                  "fixed": "6.6.31"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.8.10"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-36888.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.613040979Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/57a01eafdcf78f6da34fad9ff075ed5dfdd9f420",
        "https://git.kernel.org/stable/c/6d559e70b3eb6623935cbe7f94c1912c1099777b",
        "https://git.kernel.org/stable/c/c57824d4fe07c2131f8c48687cbd5ee2be60c767",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/36xxx/CVE-2024-36888.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-36888",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/36xxx/CVE-2024-36888.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-36888",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 488930,
  "published_at": "2024-05-30T15:28:56.214+00:00"
}