CVE-2025-71109 (GCVE-0-2025-71109)
Vulnerability from cvelistv5
Published
2026-01-14 15:05
Modified
2026-02-09 08:35
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits Since commit e424054000878 ("MIPS: Tracing: Reduce the overhead of dynamic Function Tracer"), the macro UASM_i_LA_mostly has been used, and this macro can generate more than 2 instructions. At the same time, the code in ftrace assumes that no more than 2 instructions can be generated, which is why it stores them in an int[2] array. However, as previously noted, the macro UASM_i_LA_mostly (and now UASM_i_LA) causes a buffer overflow when _mcount is beyond 32 bits. This leads to corruption of the variables located in the __read_mostly section. This corruption was observed because the variable __cpu_primary_thread_mask was corrupted, causing a hang very early during boot. This fix prevents the corruption by avoiding the generation of instructions if they could exceed 2 instructions in length. Fortunately, insn_la_mcount is only used if the instrumented code is located outside the kernel code section, so dynamic ftrace can still be used, albeit in a more limited scope. This is still preferable to corrupting memory and/or crashing the kernel.
References
Impacted products
Vendor Product Version
Linux Linux Version: e424054000878d7eb11e44289242886d6e219d22
Version: e424054000878d7eb11e44289242886d6e219d22
Version: e424054000878d7eb11e44289242886d6e219d22
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/mips/kernel/ftrace.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e3e33ac2eb69d595079a1a1e444c2fb98efdd42d",
              "status": "affected",
              "version": "e424054000878d7eb11e44289242886d6e219d22",
              "versionType": "git"
            },
            {
              "lessThan": "7f39b9d0e86ed6236b9a5fb67616ab1f76c4f150",
              "status": "affected",
              "version": "e424054000878d7eb11e44289242886d6e219d22",
              "versionType": "git"
            },
            {
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/mips/kernel/ftrace.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.35"
            },
            {
              "lessThan": "2.6.35",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.64",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.64",
                  "versionStartIncluding": "2.6.35",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.3",
                  "versionStartIncluding": "2.6.35",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.19",
                  "versionStartIncluding": "2.6.35",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nMIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits\n\nSince commit e424054000878 (\"MIPS: Tracing: Reduce the overhead of\ndynamic Function Tracer\"), the macro UASM_i_LA_mostly has been used,\nand this macro can generate more than 2 instructions. At the same\ntime, the code in ftrace assumes that no more than 2 instructions can\nbe generated, which is why it stores them in an int[2] array. However,\nas previously noted, the macro UASM_i_LA_mostly (and now UASM_i_LA)\ncauses a buffer overflow when _mcount is beyond 32 bits. This leads to\ncorruption of the variables located in the __read_mostly section.\n\nThis corruption was observed because the variable\n__cpu_primary_thread_mask was corrupted, causing a hang very early\nduring boot.\n\nThis fix prevents the corruption by avoiding the generation of\ninstructions if they could exceed 2 instructions in\nlength. Fortunately, insn_la_mcount is only used if the instrumented\ncode is located outside the kernel code section, so dynamic ftrace can\nstill be used, albeit in a more limited scope. This is still\npreferable to corrupting memory and/or crashing the kernel."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-09T08:35:03.334Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e3e33ac2eb69d595079a1a1e444c2fb98efdd42d"
        },
        {
          "url": "https://git.kernel.org/stable/c/7f39b9d0e86ed6236b9a5fb67616ab1f76c4f150"
        },
        {
          "url": "https://git.kernel.org/stable/c/36dac9a3dda1f2bae343191bc16b910c603cac25"
        }
      ],
      "title": "MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-71109",
    "datePublished": "2026-01-14T15:05:57.236Z",
    "dateReserved": "2026-01-13T15:30:19.652Z",
    "dateUpdated": "2026-02-09T08:35:03.334Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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