GHSA-358C-95R2-55GW

Vulnerability from github – Published: 2026-09-24 18:31 – Updated: 2026-09-24 18:31
VLAI
Details

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

ocfs2: fix circular locking dependency in ocfs2_init_acl()

A lockdep warning indicates a circular locking dependency between &oi->ip_xattr_sem and &journal->j_trans_barrier:

WARNING: possible circular locking dependency detected is trying to acquire lock: (&oi->ip_xattr_sem){++++}-{4:4}, at: ocfs2_init_acl+0x2fd/0x7e0 fs/ocfs2/acl.c:367

but task is already holding lock: (&journal->j_trans_barrier){.+.+}-{4:4}, at: ocfs2_start_trans+0x3ab/0x700 fs/ocfs2/journal.c:369

The deadlock involves two code paths: Path 1 (setxattr) where ocfs2_xattr_set() acquires ip_xattr_sem (write) and then starts a transaction, which acquires j_trans_barrier (read); and Path 2 (mkdir/mknod) where ocfs2_mknod() starts a transaction (j_trans_barrier read) and then calls ocfs2_init_acl(), which attempts to acquire ip_xattr_sem (read) on the parent directory to retrieve the default ACL.

Because rw_semaphores are subject to writer priority, a pending writer on j_trans_barrier (e.g., the journal commit thread) can cause Path 1 to block, while Path 2 is blocked waiting for Path 1 to release ip_xattr_sem.

The patch fixes the lock ordering by precomputing the ACL state before starting the OCFS2 transaction, while preserving POSIX ACL storage semantics and the existing inode/security initialization order. By reading the parent directory's default ACL and preparing the new inode's ACLs outside the transaction, ip_xattr_sem is always acquired before j_trans_barrier.

struct ocfs2_acl_state encapsulates the prepared ACL state, while ocfs2_acl_init_prepare() and ocfs2_acl_init_release() avoid code duplication between ocfs2_mknod() and ocfs2_init_security_and_acl(). ocfs2_calc_xattr_init() and ocfs2_init_acl() use this precomputed state, removing internal ip_xattr_sem acquisition and redundant disk reads.

Additionally, remove the ip_xattr_sem acquisition from ocfs2_xattr_set_handle(). This function is only used while initializing a new inode that has not yet been inserted into the inode hash or attached to a dentry, meaning there is no risk of concurrent access and the lock is unnecessary.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-93252"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-24T16:17:21Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix circular locking dependency in ocfs2_init_acl()\n\nA lockdep warning indicates a circular locking dependency between\n`\u0026oi-\u003eip_xattr_sem` and `\u0026journal-\u003ej_trans_barrier`:\n\nWARNING: possible circular locking dependency detected\nis trying to acquire lock:\n (\u0026oi-\u003eip_xattr_sem){++++}-{4:4}, at: ocfs2_init_acl+0x2fd/0x7e0\n fs/ocfs2/acl.c:367\n\nbut task is already holding lock:\n (\u0026journal-\u003ej_trans_barrier){.+.+}-{4:4}, at: ocfs2_start_trans+0x3ab/0x700\n fs/ocfs2/journal.c:369\n\nThe deadlock involves two code paths: Path 1 (setxattr) where\n`ocfs2_xattr_set()` acquires `ip_xattr_sem` (write) and then starts a\ntransaction, which acquires `j_trans_barrier` (read); and Path 2\n(mkdir/mknod) where `ocfs2_mknod()` starts a transaction (`j_trans_barrier`\nread) and then calls `ocfs2_init_acl()`, which attempts to acquire\n`ip_xattr_sem` (read) on the parent directory to retrieve the default ACL.\n\nBecause rw_semaphores are subject to writer priority, a pending writer on\n`j_trans_barrier` (e.g., the journal commit thread) can cause Path 1 to\nblock, while Path 2 is blocked waiting for Path 1 to release\n`ip_xattr_sem`.\n\nThe patch fixes the lock ordering by precomputing the ACL state before\nstarting the OCFS2 transaction, while preserving POSIX ACL storage\nsemantics and the existing inode/security initialization order. By reading\nthe parent directory\u0027s default ACL and preparing the new inode\u0027s ACLs\noutside the transaction, `ip_xattr_sem` is always acquired before\n`j_trans_barrier`.\n\n`struct ocfs2_acl_state` encapsulates the prepared ACL state, while\n`ocfs2_acl_init_prepare()` and `ocfs2_acl_init_release()` avoid code\nduplication between `ocfs2_mknod()` and `ocfs2_init_security_and_acl()`.\n`ocfs2_calc_xattr_init()` and `ocfs2_init_acl()` use this precomputed\nstate, removing internal `ip_xattr_sem` acquisition and redundant disk\nreads.\n\nAdditionally, remove the `ip_xattr_sem` acquisition from\n`ocfs2_xattr_set_handle()`. This function is only used while initializing a\nnew inode that has not yet been inserted into the inode hash or attached to\na dentry, meaning there is no risk of concurrent access and the lock is\nunnecessary.",
  "id": "GHSA-358c-95r2-55gw",
  "modified": "2026-09-24T18:31:24Z",
  "published": "2026-09-24T18:31:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93252"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1222f7a3183b35c0c566899fdaead5c7c4043076"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4936d4464d1ae10b5fbba64374085a0dcc060560"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5b7b3c50c39ad0dc27e7418981e01c4183273f89"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8931403ee3dcfe8a24a5267efec9d9460ab7a1b5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8d88f52fbbbcc18adf4091a955511d0cf605bf11"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bd7c05fb4a4776dff5a87b19008d28458647d15d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/caf3056936fb8b5ce92e419cf8b246ce9c437343"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f8747d81aa6d3efe3ee339a9d912ff3ca6e4d758"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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