btrfs: fix error propagation of split bios

{
  "id": "0ae2d922fea5a2ae3d8b80e7f2085c0dae0bec4bdd3f1e64eb1ccfd5f72cf2cc",
  "url": "https://osv.dev/vulnerability/CVE-2024-50225",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "btrfs: fix error propagation of split bios",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: btrfs: fix error propagation of split bios The purpose of btrfs_bbio_propagate_error() shall be propagating an error of split bio to its original btrfs_bio, and tell the error to the upper layer. However, it's not working well on some cases. * Case 1. Immediate (or quick) end_bio with an error When btrfs sends btrfs_bio to mirrored devices, btrfs calls btrfs_bio_end_io() when all the mirroring bios are completed. If that btrfs_bio was split, it is from btrfs_clone_bioset and its end_io function is btrfs_orig_write_end_io. For this case, btrfs_bbio_propagate_error() accesses the orig_bbio's bio context to increase the error count. That works well in most cases. However, if the end_io is called enough fast, orig_bbio's (remaining part after split) bio context may not be properly set at that time. Since the bio context is set when the orig_bbio (the last btrfs_bio) is sent to devices, that might be too late for earlier split btrfs_bio's completion. That will result in NULL pointer dereference. That bug is easily reproducible by running btrfs/146 on zoned devices [1] and it shows the following trace. [1] You need raid-stripe-tree feature as it create \"-d raid0 -m raid1\" FS. BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 UID: 0 PID: 13 Comm: kworker/u32:1 N",
    "evidence": "osv:CVE-2024-50225",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.11.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2024-50225",
      "aliases": [
        "CVE-2024-50225"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "852eee62d31abd695cd43e1b875d664ed292a8ca"
                },
                {
                  "fixed": "22833d89b780ba0f9f66e19c477e7decf638edce"
                },
                {
                  "fixed": "d48e1dea3931de64c26717adc2b89743c7ab6594"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.3.0"
                },
                {
                  "fixed": "6.11.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50225.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:24.129709344Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/22833d89b780ba0f9f66e19c477e7decf638edce",
        "https://git.kernel.org/stable/c/d48e1dea3931de64c26717adc2b89743c7ab6594",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50225.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-50225",
        "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/2024/50xxx/CVE-2024-50225.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-50225",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 490410,
  "published_at": "2024-11-09T10:14:36.065+00:00"
}