Vulnerability-Lookup

GHSA-72W6-32C7-VF7P

Vulnerability from github – Published: 2026-01-13 18:31 – Updated: 2026-01-13 18:31

Details

In the Linux kernel, the following vulnerability has been resolved:

ublk: fix deadlock when reading partition table

When one process(such as udev) opens ublk block device (e.g., to read the partition table via bdev_open()), a deadlock[1] can occur:

bdev_open() grabs disk->open_mutex
The process issues read I/O to ublk backend to read partition table
In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request() runs bio->bi_end_io() callbacks
If this triggers fput() on file descriptor of ublk block device, the work may be deferred to current task's task work (see fput() implementation)
This eventually calls blkdev_release() from the same context
blkdev_release() tries to grab disk->open_mutex again
Deadlock: same task waiting for a mutex it already holds

The fix is to run blk_update_request() and blk_mq_end_request() with bottom halves disabled. This forces blkdev_release() to run in kernel work-queue context instead of current task work context, and allows ublk server to make forward progress, and avoids the deadlock.

[axboe: rewrite comment in ublk]

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68823"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-01-13T16:16:04Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix deadlock when reading partition table\n\nWhen one process(such as udev) opens ublk block device (e.g., to read\nthe partition table via bdev_open()), a deadlock[1] can occur:\n\n1. bdev_open() grabs disk-\u003eopen_mutex\n2. The process issues read I/O to ublk backend to read partition table\n3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()\n   runs bio-\u003ebi_end_io() callbacks\n4. If this triggers fput() on file descriptor of ublk block device, the\n   work may be deferred to current task\u0027s task work (see fput() implementation)\n5. This eventually calls blkdev_release() from the same context\n6. blkdev_release() tries to grab disk-\u003eopen_mutex again\n7. Deadlock: same task waiting for a mutex it already holds\n\nThe fix is to run blk_update_request() and blk_mq_end_request() with bottom\nhalves disabled. This forces blkdev_release() to run in kernel work-queue\ncontext instead of current task work context, and allows ublk server to make\nforward progress, and avoids the deadlock.\n\n[axboe: rewrite comment in ublk]",
  "id": "GHSA-72w6-32c7-vf7p",
  "modified": "2026-01-13T18:31:05Z",
  "published": "2026-01-13T18:31:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68823"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0460e09a614291f06c008443f47393c37b7358e7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c258f5c4502c9667bccf5d76fa731ab9c96687c1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2025-68823 (GCVE-0-2025-68823)

Vulnerability from cvelistv5 – Published: 2026-01-13 15:29 – Updated: 2026-01-13 15:29

Title

ublk: fix deadlock when reading partition table

Summary

In the Linux kernel, the following vulnerability has been resolved: ublk: fix deadlock when reading partition table When one process(such as udev) opens ublk block device (e.g., to read the partition table via bdev_open()), a deadlock[1] can occur: 1. bdev_open() grabs disk->open_mutex 2. The process issues read I/O to ublk backend to read partition table 3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request() runs bio->bi_end_io() callbacks 4. If this triggers fput() on file descriptor of ublk block device, the work may be deferred to current task's task work (see fput() implementation) 5. This eventually calls blkdev_release() from the same context 6. blkdev_release() tries to grab disk->open_mutex again 7. Deadlock: same task waiting for a mutex it already holds The fix is to run blk_update_request() and blk_mq_end_request() with bottom halves disabled. This forces blkdev_release() to run in kernel work-queue context instead of current task work context, and allows ublk server to make forward progress, and avoids the deadlock. [axboe: rewrite comment in ublk]

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/0460e09a614291f06…
	https://git.kernel.org/stable/c/c258f5c4502c9667b…

Impacted products

Vendor

Product

Version

Linux

Affected: 71f28f3136aff5890cd56de78abc673f8393cad9 , < 0460e09a614291f06c008443f47393c37b7358e7 (git)
Affected: 71f28f3136aff5890cd56de78abc673f8393cad9 , < c258f5c4502c9667bccf5d76fa731ab9c96687c1 (git)

Linux

Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 6.18.3 , ≤ 6.18.* (semver)
Unaffected: 6.19-rc2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/ublk_drv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0460e09a614291f06c008443f47393c37b7358e7",
              "status": "affected",
              "version": "71f28f3136aff5890cd56de78abc673f8393cad9",
              "versionType": "git"
            },
            {
              "lessThan": "c258f5c4502c9667bccf5d76fa731ab9c96687c1",
              "status": "affected",
              "version": "71f28f3136aff5890cd56de78abc673f8393cad9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/ublk_drv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.3",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19-rc2",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix deadlock when reading partition table\n\nWhen one process(such as udev) opens ublk block device (e.g., to read\nthe partition table via bdev_open()), a deadlock[1] can occur:\n\n1. bdev_open() grabs disk-\u003eopen_mutex\n2. The process issues read I/O to ublk backend to read partition table\n3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()\n   runs bio-\u003ebi_end_io() callbacks\n4. If this triggers fput() on file descriptor of ublk block device, the\n   work may be deferred to current task\u0027s task work (see fput() implementation)\n5. This eventually calls blkdev_release() from the same context\n6. blkdev_release() tries to grab disk-\u003eopen_mutex again\n7. Deadlock: same task waiting for a mutex it already holds\n\nThe fix is to run blk_update_request() and blk_mq_end_request() with bottom\nhalves disabled. This forces blkdev_release() to run in kernel work-queue\ncontext instead of current task work context, and allows ublk server to make\nforward progress, and avoids the deadlock.\n\n[axboe: rewrite comment in ublk]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-13T15:29:25.392Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0460e09a614291f06c008443f47393c37b7358e7"
        },
        {
          "url": "https://git.kernel.org/stable/c/c258f5c4502c9667bccf5d76fa731ab9c96687c1"
        }
      ],
      "title": "ublk: fix deadlock when reading partition table",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68823",
    "datePublished": "2026-01-13T15:29:25.392Z",
    "dateReserved": "2025-12-24T10:30:51.048Z",
    "dateUpdated": "2026-01-13T15:29:25.392Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-72W6-32C7-VF7P

CVE-2025-68823 (GCVE-0-2025-68823)

Tags

Sightings

Nomenclature