xfs: fix cursor and pointer handling when recovering iunlink buckets

{
  "id": "975662d6fe32a5d1eeb345ff736ffd1f02c054434481e31f0e5e6475e5b14fac",
  "url": "https://osv.dev/vulnerability/CVE-2026-98443",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "xfs: fix cursor and pointer handling when recovering iunlink buckets",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: xfs: fix cursor and pointer handling when recovering iunlink buckets LOLLM pointed out a bug in xlog_recover_iunlink_bucket: 1. We don't null out prev_ip after releasing it, which can lead to UAF problems if the inodegc flush call in the loop fails. at which point I noticed even more bugs: 2. If the inodegc flush inside the loop fails, we also leak @ip. 3. We set prev_agino to agino having already advanced agino, which results in inodes with i_prev_unlinked set to itself. 4. If we exit the bottom of the loop with prev_ip set, then prev_ip aliases ip and we also set its i_prev_unlinked to itself. Bugs 3 and 4 introduce loops into the unlinked list, though these loops don't surface because we immediately flush each unlinked inode after loading it. Fix all of these issues.",
    "evidence": "osv:CVE-2026-98443",
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      "modified": "2026-11-01T02:30:49.042207430Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/47a948ba653a463d429e02fda2f06a3d6b78666d",
        "https://git.kernel.org/stable/c/65f39d09d73718611cee40399179323b5d4ead00",
        "https://git.kernel.org/stable/c/66a2179d02668f8df44b1a249899006f3ba38ea0",
        "https://git.kernel.org/stable/c/8c9d5b8a96d6b93eb24e07b4163c89341ba29bd1",
        "https://git.kernel.org/stable/c/8cfde7b2fb7288f4f6b90293e8702ff897c682fe",
        "https://git.kernel.org/stable/c/961c717e6bf0e53c2c2b1fe4aef1add9390fedab",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98443.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98443",
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  "source_id": "core-osv",
  "document_id": 518131,
  "published_at": "2026-10-18T15:14:53.597+00:00"
}