ceph: only d_add() negative dentries when they are unhashed

{
  "id": "205ba31b48f53663ddad916206ec320e591a31785ba536863a408cd6cf678cb3",
  "url": "https://osv.dev/vulnerability/CVE-2026-46052",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ceph: only d_add() negative dentries when they are unhashed",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ceph: only d_add() negative dentries when they are unhashed Ceph can call d_add(dentry, NULL) on a negative dentry that is already present in the primary dcache hash. In the current VFS that is not safe. d_add() goes through __d_add() to __d_rehash(), which unconditionally reinserts dentry->d_hash into the hlist_bl bucket. If the dentry is already hashed, reinserting the same node can corrupt the bucket, including creating a self-loop. Once that happens, __d_lookup() can spin forever in the hlist_bl walk, typically looping only on the d_name.hash mismatch check and eventually triggering RCU stall reports like this one: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 87-....: (2100 ticks this GP) idle=3a4c/1/0x4000000000000000 softirq=25003319/25003319 fqs=829 rcu: (t=2101 jiffies g=79058445 q=698988 ncpus=192) CPU: 87 UID: 2952868916 PID: 3933303 Comm: php-cgi8.3 Not tainted 6.18.17-i1-amd #950 NONE Hardware name: Dell Inc. PowerEdge R7615/0G9DHV, BIOS 1.6.6 09/22/2023 RIP: 0010:__d_lookup+0x46/0xb0 Code: c1 e8 07 48 8d 04 c2 48 8b 00 49 89 fc 49 89 f5 48 89 c3 48 83 e3 fe 48 83 f8 01 77 0f eb 2d 0f 1f 44 00 00 48 8b 1b 48 85 db <74> 20 39 6b 18 75 f3 48 8d 7b 78 e8 ba 85 d0 00 4c 39 63 10 74 1f RSP: 0018:ff745a70c8253898 EFLAGS: 00000282 RAX: ff26e470054cb208 RBX: ff26e470054cb208 RCX: 000000006e958966 RDX: ff26e48267340000 RSI: ff745a70c82539b0 RDI: ff26e458f74655c0 RBP: 000000006e958966 R08: 000000000",
    "evidence": "osv:CVE-2026-46052",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.259",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.210",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.176",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.140",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.86",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.27",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-46052",
      "aliases": [
        "CVE-2026-46052"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "2817b000b02c5f0c05af67c01fb2684e1381d6ef"
                },
                {
                  "fixed": "4147ae08824cc8b65d2b2018f79d416af2937108"
                },
                {
                  "fixed": "73b47a1f06dee5e61b00dee5227d75d3f1f6d977"
                },
                {
                  "fixed": "79ffcbeac6bc1dc1bcdb0434acf250f6215ec111"
                },
                {
                  "fixed": "83ce43a21bb7df8dd52228afdd918d2d058eefde"
                },
                {
                  "fixed": "4179cc390dacebc87079419ec92f86f3dc46294d"
                },
                {
                  "fixed": "b91e535f208c48a5e7464f1aa38338a30e7912df"
                },
                {
                  "fixed": "2010cb06b9df7d3c816c78358c566bdacbdf38ff"
                },
                {
                  "fixed": "803447f93d75ab6e40c85e6d12b5630d281d70d6"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46052.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.34"
                },
                {
                  "fixed": "5.10.259"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.210"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.176"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.140"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.86"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.27"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.0.4"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46052.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.522377512Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2010cb06b9df7d3c816c78358c566bdacbdf38ff",
        "https://git.kernel.org/stable/c/4147ae08824cc8b65d2b2018f79d416af2937108",
        "https://git.kernel.org/stable/c/4179cc390dacebc87079419ec92f86f3dc46294d",
        "https://git.kernel.org/stable/c/73b47a1f06dee5e61b00dee5227d75d3f1f6d977",
        "https://git.kernel.org/stable/c/79ffcbeac6bc1dc1bcdb0434acf250f6215ec111",
        "https://git.kernel.org/stable/c/803447f93d75ab6e40c85e6d12b5630d281d70d6",
        "https://git.kernel.org/stable/c/83ce43a21bb7df8dd52228afdd918d2d058eefde",
        "https://git.kernel.org/stable/c/b91e535f208c48a5e7464f1aa38338a30e7912df",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46052.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-46052",
        "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/2026/46xxx/CVE-2026-46052.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-46052",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 516752,
  "published_at": "2026-05-27T12:57:10.777+00:00"
}