{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-40953",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2024-40953"
  ],
  "published": "2024-07-12T12:32:42Z",
  "summary": "KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()\n\nUse {READ,WRITE}_ONCE() to access kvm->last_boosted_vcpu to ensure the\nloads and stores are atomic.  In the extremely unlikely scenario the\ncompiler tears the stores, it's theoretically possible for KVM to attempt\nto get a vCPU using an out-of-bounds index, e.g. if the write is split\ninto multiple 8-bit stores, and is paired with a 32-bit load on a VM with\n257 vCPUs:\n\n  CPU0                              CPU1\n  last_boosted_vcpu = 0xff;\n\n                                    (last_boosted_vcpu = 0x100)\n                                    last_boosted_vcpu[15:8] = 0x01;\n  i = (last_boosted_vcpu = 0x1ff)\n                                    last_boosted_vcpu[7:0] = 0x00;\n\n  vcpu = kvm->vcpu_array[0x1ff];\n\nAs detected by KCSAN:\n\n  BUG: KCSAN: data-race in kvm_vcpu_on_spin [kvm] / kvm_vcpu_on_spin [kvm]\n\n  write to 0xffffc90025a92344 of 4 bytes by task 4340 on cpu 16:\n  kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4112) kvm\n  handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel\n  vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:?\n\t\t arch/x86/kvm/vmx/vmx.c:6606) kvm_intel\n  vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm\n  kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm\n  kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm\n  __se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890)\n  __x64_sys_ioctl (fs/ioctl.c:890)\n  x64_sys_call (arch/x86/entry/syscall_64.c:33)\n  do_syscall_64 (arch/x86/entry/common.c:?)\n  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\n  read to 0xffffc90025a92344 of 4 bytes by task 4342 on cpu 4:\n  kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4069) kvm\n  handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel\n  vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:?\n\t\t\tarch/x86/kvm/vmx/vmx.c:6606) kvm_intel\n  vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm\n  kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm\n  kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm\n  __se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890)\n  __x64_sys_ioctl (fs/ioctl.c:890)\n  x64_sys_call (arch/x86/entry/syscall_64.c:33)\n  do_syscall_64 (arch/x86/entry/common.c:?)\n  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\n  value changed: 0x00000012 -> 0x00000000",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.21-1+rpt1",
        "1:6.1.47-1+rpt2",
        "1:6.1.47-1+rpt4",
        "1:6.1.54-1+rpt2",
        "1:6.1.58-1+rpt2",
        "1:6.1.63-1+rpt1",
        "1:6.1.73-1+rpt1",
        "1:6.6.20-1+rpt1",
        "1:6.6.28-1+rpt1",
        "1:6.6.31-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v8",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi2-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt2"
          },
          {
            "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"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi4-rpi-2712",
            "binary_version": "1:6.1.54-1+rpt2"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi4-rpi-v8",
            "binary_version": "1:6.1.54-1+rpt2"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi6-rpi-2712",
            "binary_version": "1:6.1.58-1+rpt2"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi6-rpi-v8",
            "binary_version": "1:6.1.58-1+rpt2"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi7-rpi-2712",
            "binary_version": "1:6.1.63-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi7-rpi-v8",
            "binary_version": "1:6.1.63-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi8-rpi-2712",
            "binary_version": "1:6.1.73-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi8-rpi-v8",
            "binary_version": "1:6.1.73-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-2712",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-v8",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.28+rpt-rpi-2712",
            "binary_version": "1:6.6.28-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.28+rpt-rpi-v8",
            "binary_version": "1:6.6.28-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.31+rpt-rpi-2712",
            "binary_version": "1:6.6.31-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.31+rpt-rpi-v8",
            "binary_version": "1:6.6.31-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.21-1+rpt1": {
            "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed",
            "upstream_version": "6.1.21",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.96"
          },
          "1:6.1.47-1+rpt2": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.96"
          },
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.96",
            "compiled_filter": false
          },
          "1:6.1.54-1+rpt2": {
            "linux_commit": "2906f7abdc03d4a92b6b0e2e0c87ea2a9dffe8f7",
            "upstream_version": "6.1.54",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.96"
          },
          "1:6.1.58-1+rpt2": {
            "linux_commit": "ccf1586ad0663fa91238ac56abf6340d6d740d18",
            "upstream_version": "6.1.58",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.96"
          },
          "1:6.1.63-1+rpt1": {
            "linux_commit": null,
            "upstream_version": "6.1.63",
            "assessment": "upstream version (no usable Linux commit)",
            "upstream_fixed": "6.1.96"
          },
          "1:6.1.73-1+rpt1": {
            "linux_commit": null,
            "upstream_version": "6.1.73",
            "assessment": "upstream version (no usable Linux commit)",
            "upstream_fixed": "6.1.96"
          },
          "1:6.6.20-1+rpt1": {
            "linux_commit": "6f16847710cc0502450788b9f12f0a14d3429668",
            "upstream_version": "6.6.20",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.6.36"
          },
          "1:6.6.28-1+rpt1": {
            "linux_commit": "0c341f47adc3578cd5f817aa20ee2b7f9ae6b23e",
            "upstream_version": "6.6.28",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.6.36"
          },
          "1:6.6.31-1+rpt1": {
            "linux_commit": "c1432b4bae5b6582f4d32ba381459f33c34d1424",
            "upstream_version": "6.6.31",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.6.36"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2024-40953"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/11a772d5376aa6d3e2e69b5b5c585f79b60c0e17"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4c141136a28421b78f34969b25a4fa32e06e2180"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/71fbc3af3dacb26c3aa2f30bb3ab05c44d082c84"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/82bd728a06e55f5b5f93d10ce67f4fe7e689853a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/92c77807d938145c7c3350c944ef9f39d7f6017c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a937ef951bba72f48d2402451419d725d70dba20"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/95c8dd79f3a14df96b3820b35b8399bd91b2be60"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/49f683b41f28918df3e51ddc0d928cb2e934ccdb"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:52:36Z"
  }
}