ghsa-4xw5-xvv7-qcv6
Vulnerability from github
Published
2025-12-24 15:30
Modified
2025-12-24 15:30
Details

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

udf: Avoid double brelse() in udf_rename()

syzbot reported a warning like below [1]:

VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 7301 at fs/buffer.c:1145 __brelse+0x67/0xa0 ... Call Trace: invalidate_bh_lru+0x99/0x150 smp_call_function_many_cond+0xe2a/0x10c0 ? generic_remap_file_range_prep+0x50/0x50 ? __brelse+0xa0/0xa0 ? __mutex_lock+0x21c/0x12d0 ? smp_call_on_cpu+0x250/0x250 ? rcu_read_lock_sched_held+0xb/0x60 ? lock_release+0x587/0x810 ? __brelse+0xa0/0xa0 ? generic_remap_file_range_prep+0x50/0x50 on_each_cpu_cond_mask+0x3c/0x80 blkdev_flush_mapping+0x13a/0x2f0 blkdev_put_whole+0xd3/0xf0 blkdev_put+0x222/0x760 deactivate_locked_super+0x96/0x160 deactivate_super+0xda/0x100 cleanup_mnt+0x222/0x3d0 task_work_run+0x149/0x240 ? task_work_cancel+0x30/0x30 do_exit+0xb29/0x2a40 ? reacquire_held_locks+0x4a0/0x4a0 ? do_raw_spin_lock+0x12a/0x2b0 ? mm_update_next_owner+0x7c0/0x7c0 ? rwlock_bug.part.0+0x90/0x90 ? zap_other_threads+0x234/0x2d0 do_group_exit+0xd0/0x2a0 __x64_sys_exit_group+0x3a/0x50 do_syscall_64+0x34/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The cause of the issue is that brelse() is called on both ofibh.sbh and ofibh.ebh by udf_find_entry() when it returns NULL. However, brelse() is called by udf_rename(), too. So, b_count on buffer_head becomes unbalanced.

This patch fixes the issue by not calling brelse() by udf_rename() when udf_find_entry() returns NULL.

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{
  "affected": [],
  "aliases": [
    "CVE-2022-50755"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-24T13:16:02Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nudf: Avoid double brelse() in udf_rename()\n\nsyzbot reported a warning like below [1]:\n\nVFS: brelse: Trying to free free buffer\nWARNING: CPU: 2 PID: 7301 at fs/buffer.c:1145 __brelse+0x67/0xa0\n...\nCall Trace:\n \u003cTASK\u003e\n invalidate_bh_lru+0x99/0x150\n smp_call_function_many_cond+0xe2a/0x10c0\n ? generic_remap_file_range_prep+0x50/0x50\n ? __brelse+0xa0/0xa0\n ? __mutex_lock+0x21c/0x12d0\n ? smp_call_on_cpu+0x250/0x250\n ? rcu_read_lock_sched_held+0xb/0x60\n ? lock_release+0x587/0x810\n ? __brelse+0xa0/0xa0\n ? generic_remap_file_range_prep+0x50/0x50\n on_each_cpu_cond_mask+0x3c/0x80\n blkdev_flush_mapping+0x13a/0x2f0\n blkdev_put_whole+0xd3/0xf0\n blkdev_put+0x222/0x760\n deactivate_locked_super+0x96/0x160\n deactivate_super+0xda/0x100\n cleanup_mnt+0x222/0x3d0\n task_work_run+0x149/0x240\n ? task_work_cancel+0x30/0x30\n do_exit+0xb29/0x2a40\n ? reacquire_held_locks+0x4a0/0x4a0\n ? do_raw_spin_lock+0x12a/0x2b0\n ? mm_update_next_owner+0x7c0/0x7c0\n ? rwlock_bug.part.0+0x90/0x90\n ? zap_other_threads+0x234/0x2d0\n do_group_exit+0xd0/0x2a0\n __x64_sys_exit_group+0x3a/0x50\n do_syscall_64+0x34/0xb0\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe cause of the issue is that brelse() is called on both ofibh.sbh\nand ofibh.ebh by udf_find_entry() when it returns NULL.  However,\nbrelse() is called by udf_rename(), too.  So, b_count on buffer_head\nbecomes unbalanced.\n\nThis patch fixes the issue by not calling brelse() by udf_rename()\nwhen udf_find_entry() returns NULL.",
  "id": "GHSA-4xw5-xvv7-qcv6",
  "modified": "2025-12-24T15:30:34Z",
  "published": "2025-12-24T15:30:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-50755"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/090bf49833c51da297ec74f98ad2bf44daea9311"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/156d440dea97deada629bb51cb17887abd862605"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/40dba68d418237b1ae2beaa06d46a94dd946278e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4fca09045509f5bde8fc28e68fbca38cb4bdcf2e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/78eba2778ae10fb2a9d450e14d26eb6f6bf1f906"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9d2cad69547abea961fa80426d600b861de1952b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c791730f2554a9ebb8f18df9368dc27d4ebc38c2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d6da7ec0f94f5208c848e0e94b70f54a0bd9c587"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e7a6a53c871460727be09f4414ccb29fb8697526"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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