btrfs: release path before iget_failed() in btrfs_read_locked_inode()

{
  "id": "e63277c6fb1028afe312147195390eb96da07801bfaba30bbf83472122a692ca",
  "url": "https://osv.dev/vulnerability/CVE-2026-23036",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "btrfs: release path before iget_failed() in btrfs_read_locked_inode()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: btrfs: release path before iget_failed() in btrfs_read_locked_inode() In btrfs_read_locked_inode() if we fail to lookup the inode, we jump to the 'out' label with a path that has a read locked leaf and then we call iget_failed(). This can result in a ABBA deadlock, since iget_failed() triggers inode eviction and that causes the release of the delayed inode, which must lock the delayed inode's mutex, and a task updating a delayed inode starts by taking the node's mutex and then modifying the inode's subvolume btree. Syzbot reported the following lockdep splat for this: ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ btrfs-cleaner/8725 is trying to acquire lock: ffff0000d6826a48 (&delayed_node->mutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290 but task is already holding lock: ffff0000dbeba878 (btrfs-tree-00){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x44/0x2ec fs/btrfs/locking.c:145 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (btrfs-tree-00){++++}-{4:4}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x198/0x39c kernel/locking/lockdep.c:5889 up_read+0x24/0x3c kernel/locking/rwsem.c:1632 btrfs_tree_read_unlock+0xdc/0x298 fs/btrfs/locking.c:169 btrfs",
    "evidence": "osv:CVE-2026-23036",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-23036",
      "aliases": [
        "CVE-2026-23036"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "69673992b1aea5540199d9b8b658ede72f55a6cf"
                },
                {
                  "fixed": "65241e3ddda60b53a4ee3ae12721fc9ee21d5827"
                },
                {
                  "fixed": "1e1f2055ad5a7a5d548789b334a4473a7665c418"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23036.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23036.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.372019708Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1e1f2055ad5a7a5d548789b334a4473a7665c418",
        "https://git.kernel.org/stable/c/65241e3ddda60b53a4ee3ae12721fc9ee21d5827",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23036.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-23036",
        "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/2026/23xxx/CVE-2026-23036.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-23036",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 521358,
  "published_at": "2026-01-31T11:42:30.782+00:00"
}