fuse: fix missing barrier when checking io-uring readiness

{
  "id": "7f669ac2d7897c6260cbaa3c53b06c6753b007647ddbc3e202313c9ca8564a00",
  "url": "https://osv.dev/vulnerability/CVE-2026-80859",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "fuse: fix missing barrier when checking io-uring readiness",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: fuse: fix missing barrier when checking io-uring readiness fuse_block_alloc() reads fch->initialized and then fch->io_uring. fch->io_uring is set before fch->initialized, ordered by the smp_wmb() in fuse_chan_set_intialized(), but fuse_block_alloc() has no matching read barrier between the two loads. This may lead a CPU to observe fch->initialized=1 but fch->io_uring=0, and skip the check that blocks request allocation until the io-uring queues are ready. This can reintroduce the lock-order inversion deadlock that commit 3393ff964e0f prevents. Add an smp_rmb() barrier to pair with the smp_wmb() in fuse_chan_set_initialized() to prevent this.",
    "evidence": "osv:CVE-2026-80859",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.51",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-80859",
      "aliases": [
        "CVE-2026-80859"
      ],
      "affected": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "8974575898cd7a4c818088f102b2e7a0286d3302"
                },
                {
                  "fixed": "dd9c835709f4bb3e4256eea7573e4e6e18f956de"
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                {
                  "fixed": "edb310bc27f0ad83e7fd558a3caf1a94ca511654"
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          "database_specific": {
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        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.14.0"
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                {
                  "fixed": "6.18.51"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
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                {
                  "fixed": "7.2.3"
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              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80859.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.625267404Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/8974575898cd7a4c818088f102b2e7a0286d3302",
        "https://git.kernel.org/stable/c/dd9c835709f4bb3e4256eea7573e4e6e18f956de",
        "https://git.kernel.org/stable/c/edb310bc27f0ad83e7fd558a3caf1a94ca511654",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80859.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-80859",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80859.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-80859",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 499725,
  "published_at": "2026-09-04T15:55:13.378+00:00"
}