GHSA-MRGJ-88F9-5G2F

Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-24 18:32
VLAI
Details

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

fsnotify: fix inode reference leak in fsnotify_recalc_mask()

fsnotify_recalc_mask() fails to handle the return value of __fsnotify_recalc_mask(), which may return an inode pointer that needs to be released via fsnotify_drop_object() when the connector's HAS_IREF flag transitions from set to cleared.

This manifests as a hung task with the following call trace:

INFO: task umount:1234 blocked for more than 120 seconds. Call Trace: __schedule schedule fsnotify_sb_delete generic_shutdown_super kill_anon_super cleanup_mnt task_work_run do_exit do_group_exit

The race window that triggers the iref leak:

Thread A (adding mark) Thread B (removing mark) ────────────────────── ──────────────────────── fsnotify_add_mark_locked(): fsnotify_add_mark_list(): spin_lock(conn->lock) add mark_B(evictable) to list spin_unlock(conn->lock) return

/* ---- gap: no lock held ---- */

                                  fsnotify_detach_mark(mark_A):
                                    spin_lock(mark_A->lock)
                                    clear ATTACHED flag on mark_A
                                    spin_unlock(mark_A->lock)
                                    fsnotify_put_mark(mark_A)

fsnotify_recalc_mask():
  spin_lock(conn->lock)
  __fsnotify_recalc_mask():
    /* mark_A skipped: ATTACHED cleared */
    /* only mark_B(evictable) remains */
    want_iref = false
    has_iref = true  /* not yet cleared */
    -> HAS_IREF transitions true -> false
    -> returns inode pointer
  spin_unlock(conn->lock)
  /* BUG: return value discarded!
   * iput() and fsnotify_put_sb_watched_objects()
   * are never called */

Fix this by deferring the transition true -> false of HAS_IREF flag from fsnotify_recalc_mask() (Thread A) to fsnotify_put_mark() (thread B).

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{
  "affected": [],
  "aliases": [
    "CVE-2026-52990"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T17:17:09Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfsnotify: fix inode reference leak in fsnotify_recalc_mask()\n\nfsnotify_recalc_mask() fails to handle the return value of\n__fsnotify_recalc_mask(), which may return an inode pointer that needs\nto be released via fsnotify_drop_object() when the connector\u0027s HAS_IREF\nflag transitions from set to cleared.\n\nThis manifests as a hung task with the following call trace:\n\n  INFO: task umount:1234 blocked for more than 120 seconds.\n  Call Trace:\n   __schedule\n   schedule\n   fsnotify_sb_delete\n   generic_shutdown_super\n   kill_anon_super\n   cleanup_mnt\n   task_work_run\n   do_exit\n   do_group_exit\n\nThe race window that triggers the iref leak:\n\n  Thread A (adding mark)              Thread B (removing mark)\n  \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500              \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\n  fsnotify_add_mark_locked():\n    fsnotify_add_mark_list():\n      spin_lock(conn-\u003elock)\n      add mark_B(evictable) to list\n      spin_unlock(conn-\u003elock)\n    return\n\n    /* ---- gap: no lock held ---- */\n\n                                      fsnotify_detach_mark(mark_A):\n                                        spin_lock(mark_A-\u003elock)\n                                        clear ATTACHED flag on mark_A\n                                        spin_unlock(mark_A-\u003elock)\n                                        fsnotify_put_mark(mark_A)\n\n    fsnotify_recalc_mask():\n      spin_lock(conn-\u003elock)\n      __fsnotify_recalc_mask():\n        /* mark_A skipped: ATTACHED cleared */\n        /* only mark_B(evictable) remains */\n        want_iref = false\n        has_iref = true  /* not yet cleared */\n        -\u003e HAS_IREF transitions true -\u003e false\n        -\u003e returns inode pointer\n      spin_unlock(conn-\u003elock)\n      /* BUG: return value discarded!\n       * iput() and fsnotify_put_sb_watched_objects()\n       * are never called */\n\nFix this by deferring the transition true -\u003e false of HAS_IREF flag from\nfsnotify_recalc_mask() (Thread A) to fsnotify_put_mark() (thread B).",
  "id": "GHSA-mrgj-88f9-5g2f",
  "modified": "2026-06-24T18:32:42Z",
  "published": "2026-06-24T18:32:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52990"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4aca914ac152f5d055ddcb36704d1e539ac08977"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5c80289503da3658e3df80280598c68d181eadbd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8c8afa6444e6bdc145d2bf2f3aeeca6da3e36b42"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b740cc86816bbc87902ae9db74cd21abde3c8d63"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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