{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-42126",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2024-42126"
  ],
  "published": "2024-07-30T07:47:52Z",
  "summary": "powerpc: Avoid nmi_enter/nmi_exit in real mode interrupt.",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc: Avoid nmi_enter/nmi_exit in real mode interrupt.\n\nnmi_enter()/nmi_exit() touches per cpu variables which can lead to kernel\ncrash when invoked during real mode interrupt handling (e.g. early HMI/MCE\ninterrupt handler) if percpu allocation comes from vmalloc area.\n\nEarly HMI/MCE handlers are called through DEFINE_INTERRUPT_HANDLER_NMI()\nwrapper which invokes nmi_enter/nmi_exit calls. We don't see any issue when\npercpu allocation is from the embedded first chunk. However with\nCONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK enabled there are chances where percpu\nallocation can come from the vmalloc area.\n\nWith kernel command line \"percpu_alloc=page\" we can force percpu allocation\nto come from vmalloc area and can see kernel crash in machine_check_early:\n\n[    1.215714] NIP [c000000000e49eb4] rcu_nmi_enter+0x24/0x110\n[    1.215717] LR [c0000000000461a0] machine_check_early+0xf0/0x2c0\n[    1.215719] --- interrupt: 200\n[    1.215720] [c000000fffd73180] [0000000000000000] 0x0 (unreliable)\n[    1.215722] [c000000fffd731b0] [0000000000000000] 0x0\n[    1.215724] [c000000fffd73210] [c000000000008364] machine_check_early_common+0x134/0x1f8\n\nFix this by avoiding use of nmi_enter()/nmi_exit() in real mode if percpu\nfirst chunk is not embedded.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.98",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2024-42126"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fb6675db04c4b79883373edc578d5df7bbc84848"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e2afb26615adf6c3ceaaa7732aa839bcd587a057"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8d3f83dfb23674540c827a8d65fba20aa300b252"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0f37946c62c48a907625348cbc720a7a0c547d1e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2c78c9411e685dbc9eac8c2845111b03501975b8"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0db880fc865ffb522141ced4bfa66c12ab1fbb70"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}