blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()

{
  "id": "4ead0c29f4077dc6e1a83a7f32516df182a9bee80081aca03169e396804edbd1",
  "url": "https://osv.dev/vulnerability/CVE-2022-50530",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping() Our syzkaller report a null pointer dereference, root cause is following: __blk_mq_alloc_map_and_rqs set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs blk_mq_alloc_map_and_rqs blk_mq_alloc_rqs // failed due to oom alloc_pages_node // set->tags[hctx_idx] is still NULL blk_mq_free_rqs drv_tags = set->tags[hctx_idx]; // null pointer dereference is triggered blk_mq_clear_rq_mapping(drv_tags, ...) This is because commit 63064be150e4 (\"blk-mq: Add blk_mq_alloc_map_and_rqs()\") merged the two steps: 1) set->tags[hctx_idx] = blk_mq_alloc_rq_map() 2) blk_mq_alloc_rqs(..., set->tags[hctx_idx]) into one step: set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs() Since tags is not initialized yet in this case, fix the problem by checking if tags is NULL pointer in blk_mq_clear_rq_mapping().",
    "evidence": "osv:CVE-2022-50530",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.0.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2022-50530",
      "aliases": [
        "CVE-2022-50530"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "63064be150e4b1ba1e4af594ef5aa81adf21a52d"
                },
                {
                  "fixed": "6a440e6d04431e774dc084abe88c106e2a474c1a"
                },
                {
                  "fixed": "76dd298094f484c6250ebd076fa53287477b2328"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50530.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.0.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50530.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.930031893Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/6a440e6d04431e774dc084abe88c106e2a474c1a",
        "https://git.kernel.org/stable/c/76dd298094f484c6250ebd076fa53287477b2328",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50530.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2022-50530",
        "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/2022/50xxx/CVE-2022-50530.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2022-50530",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 497903,
  "published_at": "2025-10-07T15:19:21.259+00:00"
}