{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "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": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "arch/powerpc/include/asm/interrupt.h",
                  "arch/powerpc/include/asm/percpu.h",
                  "arch/powerpc/kernel/setup_64.c"
               ],
               "versions": [
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "fb6675db04c4",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "e2afb26615ad",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "8d3f83dfb236",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "0f37946c62c4",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "2c78c9411e68",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "0db880fc865f",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "arch/powerpc/include/asm/interrupt.h",
                  "arch/powerpc/include/asm/percpu.h",
                  "arch/powerpc/kernel/setup_64.c"
               ],
               "versions": [
                  {
                     "version": "5.10.224",
                     "lessThanOrEqual": "5.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15.165",
                     "lessThanOrEqual": "5.15.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.1.98",
                     "lessThanOrEqual": "6.1.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.6.39",
                     "lessThanOrEqual": "6.6.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.9.9",
                     "lessThanOrEqual": "6.9.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.10",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/fb6675db04c4b79883373edc578d5df7bbc84848"
            },
            {
               "url": "https://git.kernel.org/stable/c/e2afb26615adf6c3ceaaa7732aa839bcd587a057"
            },
            {
               "url": "https://git.kernel.org/stable/c/8d3f83dfb23674540c827a8d65fba20aa300b252"
            },
            {
               "url": "https://git.kernel.org/stable/c/0f37946c62c48a907625348cbc720a7a0c547d1e"
            },
            {
               "url": "https://git.kernel.org/stable/c/2c78c9411e685dbc9eac8c2845111b03501975b8"
            },
            {
               "url": "https://git.kernel.org/stable/c/0db880fc865ffb522141ced4bfa66c12ab1fbb70"
            }
         ],
         "title": "powerpc: Avoid nmi_enter/nmi_exit in real mode interrupt.",
         "x_generator": {
            "engine": "bippy-c9c4e1df01b2"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-42126",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}