CVE-2026-90400 (GCVE-0-2026-90400)
Vulnerability from cvelistv5
Published
2026-09-17 16:09
Modified
2026-10-19 09:03
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: md: recheck spare changes before starting sync remove_spares() and remove_and_add_spares() modify the array's rdev configuration. These operations are only safe after the array has been suspended. md_start_sync() checks whether spare configuration changes are needed before taking reconfig_mutex. However, the rdev state can change before the mutex is acquired, so the initial check can become stale. In that case, md_choose_sync_action() may remove or replace rdevs while normal I/O is still accessing them. The race can occur as follows: raid10d Worker Normal IO ____________ _______________________ ______________________ raid10_write_request() wait_blocked_dev() set Blocked set Faulty Skip Faulty rdev rrdev->nr_pending++ .repl_bio = bio removeable_rdev = false . array not suspended . lock mddev goto err_handle lock mddev (wait) . update sb . clear Blocked . . unlock mddev . lock mddev (acquires) remove_spares() removeable_rdev = true raid10_remove_disk() rdev = replacement replacement = NULL rdev_dec_pending(NULL) unlock mddev (NULL)->nr_pending-- In this case, rdev_dec_pending() is called with a NULL pointer, resulting in a NULL pointer dereference when attempting to decrement nr_pending. Fix this by suspending the array when spare configuration changes are needed, including for non-read-write arrays, and checking again after taking reconfig_mutex. If the array was not already suspended and a change is now needed, release the mutex, suspend the array, and reacquire the mutex before continuing.
References
Impacted products
Vendor Product Version
Linux Linux Version: bc08041b32abe6c9824f78735bac22018eabfc06
Version: bc08041b32abe6c9824f78735bac22018eabfc06
Version: bc08041b32abe6c9824f78735bac22018eabfc06
Version: bc08041b32abe6c9824f78735bac22018eabfc06
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/md.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c3777d16bc3335c0ac4bdad0551c80d38c5d94cc",
              "status": "affected",
              "version": "bc08041b32abe6c9824f78735bac22018eabfc06",
              "versionType": "git"
            },
            {
              "lessThan": "e5ac7ab78467b064f1da8b0f3042a63595fafcfd",
              "status": "affected",
              "version": "bc08041b32abe6c9824f78735bac22018eabfc06",
              "versionType": "git"
            },
            {
              "lessThan": "81b39df5d701976cf20e52f33106c1fc1603b4cb",
              "status": "affected",
              "version": "bc08041b32abe6c9824f78735bac22018eabfc06",
              "versionType": "git"
            },
            {
              "lessThan": "c7d34d17ea43ebc86b45d439ebb435e11ca44bca",
              "status": "affected",
              "version": "bc08041b32abe6c9824f78735bac22018eabfc06",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/md.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
            {
              "lessThan": "6.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd: recheck spare changes before starting sync\n\nremove_spares() and remove_and_add_spares() modify the array\u0027s rdev\nconfiguration. These operations are only safe after the array has been\nsuspended.\n\nmd_start_sync() checks whether spare configuration changes are needed\nbefore taking reconfig_mutex. However, the rdev state can change before\nthe mutex is acquired, so the initial check can become stale. In that\ncase, md_choose_sync_action() may remove or replace rdevs while normal\nI/O is still accessing them.\n\nThe race can occur as follows:\n\nraid10d          Worker                      Normal IO\n____________     _______________________     ______________________\n\n                                             raid10_write_request()\n                                             wait_blocked_dev()\nset Blocked\nset Faulty\n                                             Skip Faulty rdev\n                                             rrdev-\u003enr_pending++\n                                             .repl_bio = bio\n                 removeable_rdev = false     .\n                 array not suspended         .\nlock mddev                                   goto err_handle\n                 lock mddev (wait)\n                 .\nupdate sb        .\nclear Blocked    .\n                 .\nunlock mddev     .\n                 lock mddev (acquires)\n                 remove_spares()\n                 removeable_rdev = true\n\n                 raid10_remove_disk()\n                 rdev = replacement\n                 replacement = NULL\n                                             rdev_dec_pending(NULL)\n                 unlock mddev                (NULL)-\u003enr_pending--\n\nIn this case, rdev_dec_pending() is called with a NULL pointer,\nresulting in a NULL pointer dereference when attempting to decrement\nnr_pending.\n\nFix this by suspending the array when spare configuration changes are\nneeded, including for non-read-write arrays, and checking again after\ntaking reconfig_mutex. If the array was not already suspended and a\nchange is now needed, release the mutex, suspend the array, and\nreacquire the mutex before continuing."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:03:04.317Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c3777d16bc3335c0ac4bdad0551c80d38c5d94cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/e5ac7ab78467b064f1da8b0f3042a63595fafcfd"
        },
        {
          "url": "https://git.kernel.org/stable/c/81b39df5d701976cf20e52f33106c1fc1603b4cb"
        },
        {
          "url": "https://git.kernel.org/stable/c/c7d34d17ea43ebc86b45d439ebb435e11ca44bca"
        }
      ],
      "title": "md: recheck spare changes before starting sync",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90400",
    "datePublished": "2026-09-17T16:09:30.915Z",
    "dateReserved": "2026-09-11T19:38:34.811Z",
    "dateUpdated": "2026-10-19T09:03:04.317Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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