GHSA-VR2G-5Q36-7736

Vulnerability from github – Published: 2026-05-28 12:30 – Updated: 2026-05-28 12:30
VLAI
Details

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

eventfs: Hold eventfs_mutex and SRCU when remount walks events

Commit 340f0c7067a9 ("eventfs: Update all the eventfs_inodes from the events descriptor") had eventfs_set_attrs() recurse through ei->children on remount. The walk only holds the rcu_read_lock() taken by tracefs_apply_options() over tracefs_inodes, which is wrong:

  • list_for_each_entry over ei->children races with the list_del_rcu() in eventfs_remove_rec() -- LIST_POISON1 deref, same shape as d2603279c7d6.
  • eventfs_inodes are freed via call_srcu(&eventfs_srcu, ...). rcu_read_lock() does not extend an SRCU grace period, so ti->private can be reclaimed under the walk.
  • The writes to ei->attr race with eventfs_set_attr(), which holds eventfs_mutex.

Reproducer:

while :; do mount -o remount,uid=$((RANDOM%1000)) /sys/kernel/tracing; done & while :; do echo "p:kp submit_bio" > /sys/kernel/tracing/kprobe_events echo > /sys/kernel/tracing/kprobe_events done

Wrap the events portion of tracefs_apply_options() in eventfs_remount_lock()/_unlock() that take eventfs_mutex and srcu_read_lock(&eventfs_srcu). eventfs_set_attrs() doesn't sleep so the nested rcu_read_lock() is fine; lockdep_assert_held() pins the contract.

Comment in tracefs_drop_inode() said "RCU cycle" -- it is SRCU.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-46106"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-28T10:16:25Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\neventfs: Hold eventfs_mutex and SRCU when remount walks events\n\nCommit 340f0c7067a9 (\"eventfs: Update all the eventfs_inodes from the\nevents descriptor\") had eventfs_set_attrs() recurse through ei-\u003echildren\non remount.  The walk only holds the rcu_read_lock() taken by\ntracefs_apply_options() over tracefs_inodes, which is wrong:\n\n  - list_for_each_entry over ei-\u003echildren races with the list_del_rcu()\n    in eventfs_remove_rec() -- LIST_POISON1 deref, same shape as\n    d2603279c7d6.\n  - eventfs_inodes are freed via call_srcu(\u0026eventfs_srcu, ...).\n    rcu_read_lock() does not extend an SRCU grace period, so ti-\u003eprivate\n    can be reclaimed under the walk.\n  - The writes to ei-\u003eattr race with eventfs_set_attr(), which holds\n    eventfs_mutex.\n\nReproducer:\n\n  while :; do mount -o remount,uid=$((RANDOM%1000)) /sys/kernel/tracing; done \u0026\n  while :; do\n      echo \"p:kp submit_bio\" \u003e /sys/kernel/tracing/kprobe_events\n      echo \u003e /sys/kernel/tracing/kprobe_events\n  done\n\nWrap the events portion of tracefs_apply_options() in\neventfs_remount_lock()/_unlock() that take eventfs_mutex and\nsrcu_read_lock(\u0026eventfs_srcu).  eventfs_set_attrs() doesn\u0027t sleep so the\nnested rcu_read_lock() is fine; lockdep_assert_held() pins the contract.\n\nComment in tracefs_drop_inode() said \"RCU cycle\" -- it is SRCU.",
  "id": "GHSA-vr2g-5q36-7736",
  "modified": "2026-05-28T12:30:28Z",
  "published": "2026-05-28T12:30:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46106"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/07004a8c4b572171934390148ee48c4175c77eed"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/44e64d8a432837308f4dda3ffe819f1ec092a0ba"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/52b109f1b875b912d4ab2c5fdd8c322d47119d9b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ae9cd0b46b1890040006a2fc5e905c5d6053fd02"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ed2ad73bcb0a7a6cc934097d4853b6d5124c317e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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