ghsa-xxcp-92h2-x7r7
Vulnerability from github
Published
2025-11-12 12:30
Modified
2025-11-12 12:30
Details

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

f2fs: fix to avoid migrating empty section

It reports a bug from device w/ zufs:

F2FS-fs (dm-64): Inconsistent segment (173822) type [1, 0] in SSA and SIT F2FS-fs (dm-64): Stopped filesystem due to reason: 4

Thread A Thread B - f2fs_expand_inode_data - f2fs_allocate_pinning_section - f2fs_gc_range - do_garbage_collect w/ segno #x - writepage - f2fs_allocate_data_block - new_curseg - allocate segno #x

The root cause is: fallocate on pinning file may race w/ block allocation as above, result in do_garbage_collect() from fallocate() may migrate segment which is just allocated by a log, the log will update segment type in its in-memory structure, however GC will get segment type from on-disk SSA block, once segment type changes by log, we can detect such inconsistency, then shutdown filesystem.

In this case, on-disk SSA shows type of segno #173822 is 1 (SUM_TYPE_NODE), however segno #173822 was just allocated as data type segment, so in-memory SIT shows type of segno #173822 is 0 (SUM_TYPE_DATA).

Change as below to fix this issue: - check whether current section is empty before gc - add sanity checks on do_garbage_collect() to avoid any race case, result in migrating segment used by log. - btw, it fixes misc issue in printed logs: "SSA and SIT" -> "SIT and SSA".

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2025-40150"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-11-12T11:15:44Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid migrating empty section\n\nIt reports a bug from device w/ zufs:\n\nF2FS-fs (dm-64): Inconsistent segment (173822) type [1, 0] in SSA and SIT\nF2FS-fs (dm-64): Stopped filesystem due to reason: 4\n\nThread A\t\t\t\tThread B\n- f2fs_expand_inode_data\n - f2fs_allocate_pinning_section\n  - f2fs_gc_range\n   - do_garbage_collect w/ segno #x\n\t\t\t\t\t- writepage\n\t\t\t\t\t - f2fs_allocate_data_block\n\t\t\t\t\t  - new_curseg\n\t\t\t\t\t   - allocate segno #x\n\nThe root cause is: fallocate on pinning file may race w/ block allocation\nas above, result in do_garbage_collect() from fallocate() may migrate\nsegment which is just allocated by a log, the log will update segment type\nin its in-memory structure, however GC will get segment type from on-disk\nSSA block, once segment type changes by log, we can detect such\ninconsistency, then shutdown filesystem.\n\nIn this case, on-disk SSA shows type of segno #173822 is 1 (SUM_TYPE_NODE),\nhowever segno #173822 was just allocated as data type segment, so in-memory\nSIT shows type of segno #173822 is 0 (SUM_TYPE_DATA).\n\nChange as below to fix this issue:\n- check whether current section is empty before gc\n- add sanity checks on do_garbage_collect() to avoid any race case, result\nin migrating segment used by log.\n- btw, it fixes misc issue in printed logs: \"SSA and SIT\" -\u003e \"SIT and SSA\".",
  "id": "GHSA-xxcp-92h2-x7r7",
  "modified": "2025-11-12T12:30:27Z",
  "published": "2025-11-12T12:30:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40150"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d625a2b08c089397d3a03bff13fa8645e4ec7a01"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eec1589be36fcf7440755703e4faeee2c01e360b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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