mm/slub: add check for s->flags in the alloc_tagging_slab_free_hook

{
  "id": "f46e780d1647e8cc4ea4e4ae3abf75ed320b83b92bad8523e9b50e49b4f18da0",
  "url": "https://osv.dev/vulnerability/CVE-2024-46789",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mm/slub: add check for s->flags in the alloc_tagging_slab_free_hook",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mm/slub: add check for s->flags in the alloc_tagging_slab_free_hook When enable CONFIG_MEMCG & CONFIG_KFENCE & CONFIG_KMEMLEAK, the following warning always occurs,This is because the following call stack occurred: mem_pool_alloc kmem_cache_alloc_noprof slab_alloc_node kfence_alloc Once the kfence allocation is successful,slab->obj_exts will not be empty, because it has already been assigned a value in kfence_init_pool. Since in the prepare_slab_obj_exts_hook function,we perform a check for s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE),the alloc_tag_add function will not be called as a result.Therefore,ref->ct remains NULL. However,when we call mem_pool_free,since obj_ext is not empty, it eventually leads to the alloc_tag_sub scenario being invoked. This is where the warning occurs. So we should add corresponding checks in the alloc_tagging_slab_free_hook. For __GFP_NO_OBJ_EXT case,I didn't see the specific case where it's using kfence,so I won't add the corresponding check in alloc_tagging_slab_free_hook for now. [ 3.734349] ------------[ cut here ]------------ [ 3.734807] alloc_tag was not set [ 3.735129] WARNING: CPU: 4 PID: 40 at ./include/linux/alloc_tag.h:130 kmem_cache_free+0x444/0x574 [ 3.735866] Modules linked in: autofs4 [ 3.736211] CPU: 4 UID: 0 PID: 40 Comm: ksoftirqd/4 Tainted: G W 6.11.0-rc3-dirty #1 [ 3.736969] Tainted: [W]=WARN [ 3.737258] Hardware name: QEMU KVM Virtual Machine, BIOS unknow",
    "evidence": "osv:CVE-2024-46789",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.10.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2024-46789",
      "aliases": [
        "CVE-2024-46789"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "4b8736964640fe160724e7135dc62883bddcdace"
                },
                {
                  "fixed": "2d476c86ba4745fcbc912ce4627df4fa80caa9ad"
                },
                {
                  "fixed": "ab7ca09520e9c41c219a4427fe0dae24024bfe7f"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-46789.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.10.0"
                },
                {
                  "fixed": "6.10.10"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-46789.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.199807004Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2d476c86ba4745fcbc912ce4627df4fa80caa9ad",
        "https://git.kernel.org/stable/c/ab7ca09520e9c41c219a4427fe0dae24024bfe7f",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/46xxx/CVE-2024-46789.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-46789",
        "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/2024/46xxx/CVE-2024-46789.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-46789",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 493646,
  "published_at": "2024-09-18T07:12:45.154+00:00"
}