powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT

{
  "id": "3c21aebfa52e655804f0a05d2a6e3a7d50ca176938477b1aef7ca16f13774a25",
  "url": "https://osv.dev/vulnerability/CVE-2023-54267",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT lppaca_shared_proc() takes a pointer to the lppaca which is typically accessed through get_lppaca(). With DEBUG_PREEMPT enabled, this leads to checking if preemption is enabled, for example: BUG: using smp_processor_id() in preemptible [00000000] code: grep/10693 caller is lparcfg_data+0x408/0x19a0 CPU: 4 PID: 10693 Comm: grep Not tainted 6.5.0-rc3 #2 Call Trace: dump_stack_lvl+0x154/0x200 (unreliable) check_preemption_disabled+0x214/0x220 lparcfg_data+0x408/0x19a0 ... This isn't actually a problem however, as it does not matter which lppaca is accessed, the shared proc state will be the same. vcpudispatch_stats_procfs_init() already works around this by disabling preemption, but the lparcfg code does not, erroring any time /proc/powerpc/lparcfg is accessed with DEBUG_PREEMPT enabled. Instead of disabling preemption on the caller side, rework lppaca_shared_proc() to not take a pointer and instead directly access the lppaca, bypassing any potential preemption checks. [mpe: Rework to avoid needing a definition in paca.h and lppaca.h]",
    "evidence": "osv:CVE-2023-54267",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "evidence": "/affected/1/ranges"
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            "value": "6.4.16",
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    "severity": "unknown",
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      "id": "CVE-2023-54267",
      "aliases": [
        "CVE-2023-54267"
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      "modified": "2026-10-28T02:30:53.041417709Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2935443dc9c28499223d8c881474259e4b998f2a",
        "https://git.kernel.org/stable/c/3c5e8e666794d7dde6d14ea846c6c04f2bb34900",
        "https://git.kernel.org/stable/c/4c8568cf4c45b415854195c8832b557cdefba57a",
        "https://git.kernel.org/stable/c/953c54dfdc5d3eb7243ed902b50acb5ea1db4355",
        "https://git.kernel.org/stable/c/eac030b22ea12cdfcbb2e941c21c03964403c63f",
        "https://git.kernel.org/stable/c/f45ee5c074013a0fbfce77a5af5efddb01f5d4f4",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/54xxx/CVE-2023-54267.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-54267",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
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        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
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  "source_id": "core-osv",
  "document_id": 521929,
  "published_at": "2025-12-30T12:15:58.914+00:00"
}