FKIE_CVE-2026-64326

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-25 10:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: block: skip sync_blockdev() on surprise removal in bdev_mark_dead() bdev_mark_dead()'s @surprise == true means the device is already gone. The filesystem callback fs_bdev_mark_dead() honours this and skips sync_filesystem(), but the bare block device path (no ->mark_dead op) lost its !surprise guard when the holder ->mark_dead callback was wired up (see Fixes), and now calls sync_blockdev() unconditionally, which can hang forever waiting on writeback that can no longer complete. syzkaller hit this via nvme_reset_work()'s "I/O queues lost" path: nvme_mark_namespaces_dead() -> blk_mark_disk_dead() -> bdev_mark_dead(bdev, true) -> sync_blockdev() blocks in folio_wait_writeback(), wedging the reset worker and every task waiting on it. Skip the sync on surprise removal, matching fs_bdev_mark_dead(); invalidate_bdev() still runs. Orderly removal (surprise == false) is unchanged. Found by FuzzNvme(Syzkaller with FEMU fuzzing framework).
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9818bcae3c0ca1dde4b9a334125c46676e0a9b29
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/aa4c4a9315764b2b7a7182e72cc5ea87520436b4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d6998ddd507c81e3829489a6ead23f17f5acb7fe
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f41cf35ee2a1e31374b3f54e7579c55153506e70
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "block/bdev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d6998ddd507c81e3829489a6ead23f17f5acb7fe",
              "status": "affected",
              "version": "d8530de5a6e82be0ce17a5fdf727a394bcf6444c",
              "versionType": "git"
            },
            {
              "lessThan": "f41cf35ee2a1e31374b3f54e7579c55153506e70",
              "status": "affected",
              "version": "d8530de5a6e82be0ce17a5fdf727a394bcf6444c",
              "versionType": "git"
            },
            {
              "lessThan": "9818bcae3c0ca1dde4b9a334125c46676e0a9b29",
              "status": "affected",
              "version": "d8530de5a6e82be0ce17a5fdf727a394bcf6444c",
              "versionType": "git"
            },
            {
              "lessThan": "aa4c4a9315764b2b7a7182e72cc5ea87520436b4",
              "status": "affected",
              "version": "d8530de5a6e82be0ce17a5fdf727a394bcf6444c",
              "versionType": "git"
            },
            {
              "lessThan": "49f06cff50a4ccf3b7a1a662ceb892b3b21a527a",
              "status": "affected",
              "version": "d8530de5a6e82be0ce17a5fdf727a394bcf6444c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "block/bdev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "lessThan": "6.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: skip sync_blockdev() on surprise removal in bdev_mark_dead()\n\nbdev_mark_dead()\u0027s @surprise == true means the device is already gone.\nThe filesystem callback fs_bdev_mark_dead() honours this and skips\nsync_filesystem(), but the bare block device path (no -\u003emark_dead op)\nlost its !surprise guard when the holder -\u003emark_dead callback was wired\nup (see Fixes), and now calls sync_blockdev() unconditionally, which can\nhang forever waiting on writeback that can no longer complete.\n\nsyzkaller hit this via nvme_reset_work()\u0027s \"I/O queues lost\" path:\nnvme_mark_namespaces_dead() -\u003e blk_mark_disk_dead() -\u003e\nbdev_mark_dead(bdev, true) -\u003e sync_blockdev() blocks in\nfolio_wait_writeback(), wedging the reset worker and every task waiting\non it.\n\nSkip the sync on surprise removal, matching fs_bdev_mark_dead();\ninvalidate_bdev() still runs. Orderly removal (surprise == false) is\nunchanged.\n\nFound by FuzzNvme(Syzkaller with FEMU fuzzing framework)."
    }
  ],
  "id": "CVE-2026-64326",
  "lastModified": "2026-07-25T10:17:14.207",
  "metrics": {},
  "published": "2026-07-25T10:17:14.207",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9818bcae3c0ca1dde4b9a334125c46676e0a9b29"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/aa4c4a9315764b2b7a7182e72cc5ea87520436b4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d6998ddd507c81e3829489a6ead23f17f5acb7fe"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f41cf35ee2a1e31374b3f54e7579c55153506e70"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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