btrfs: release correct delalloc amount in direct IO write path

{
  "id": "cce8b35f7b12a5f4eb5dfa17bf839cfa6e754d1b57ca8d4150a5304754ec0b83",
  "url": "https://osv.dev/vulnerability/CVE-2022-49068",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "btrfs: release correct delalloc amount in direct IO write path",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: btrfs: release correct delalloc amount in direct IO write path Running generic/406 causes the following WARNING in btrfs_destroy_inode() which tells there are outstanding extents left. In btrfs_get_blocks_direct_write(), we reserve a temporary outstanding extents with btrfs_delalloc_reserve_metadata() (or indirectly from btrfs_delalloc_reserve_space(()). We then release the outstanding extents with btrfs_delalloc_release_extents(). However, the \"len\" can be modified in the COW case, which releases fewer outstanding extents than expected. Fix it by calling btrfs_delalloc_release_extents() for the original length. To reproduce the warning, the filesystem should be 1 GiB. It's triggering a short-write, due to not being able to allocate a large extent and instead allocating a smaller one. WARNING: CPU: 0 PID: 757 at fs/btrfs/inode.c:8848 btrfs_destroy_inode+0x1e6/0x210 [btrfs] Modules linked in: btrfs blake2b_generic xor lzo_compress lzo_decompress raid6_pq zstd zstd_decompress zstd_compress xxhash zram zsmalloc CPU: 0 PID: 757 Comm: umount Not tainted 5.17.0-rc8+ #101 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS d55cb5a 04/01/2014 RIP: 0010:btrfs_destroy_inode+0x1e6/0x210 [btrfs] RSP: 0018:ffffc9000327bda8 EFLAGS: 00010206 RAX: 0000000000000000 RBX: ffff888100548b78 RCX: 0000000000000000 RDX: 0000000000026900 RSI: 0000000000000000 RDI: ffff888100548b78 RBP: ffff888100548940 R08: 0000000000000000 R",
    "evidence": "osv:CVE-2022-49068",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.35",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.17.4",
            "evidence": "/affected/1/ranges"
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    "severity": "unknown",
    "structured": {
      "id": "CVE-2022-49068",
      "aliases": [
        "CVE-2022-49068"
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            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:30.556110317Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/07cacfd9d9dc134557ac8866c73d570a59b3d1f3",
        "https://git.kernel.org/stable/c/6d82ad13c4110e73c7b0392f00534a1502a1b520",
        "https://git.kernel.org/stable/c/a04d37ddfe4be431b9e52e8504490376ab0a39a4",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49068.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2022-49068",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49068.json"
      }
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    "related_cves": [
      {
        "value": "CVE-2022-49068",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 497407,
  "published_at": "2025-02-26T01:54:35.34+00:00"
}