CVE-2026-74365 (GCVE-0-2026-74365)
Vulnerability from cvelistv5
Published
2026-08-15 05:58
Modified
2026-08-17 05:46
Summary
In the Linux kernel, the following vulnerability has been resolved: nvdimm/btt: Handle preemption in BTT lane acquisition BTT lanes serialize access to per-lane metadata and workspace state during BTT I/O. The btt-check unit test reports data mismatches during BTT writes due to a race in lane acquisition that can lead to silent data corruption. The existing lane model uses a spinlock together with a per-CPU recursion count. That recursion model stopped being valid after BTT lanes became preemptible: another task can run on the same CPU, observe a non-zero recursion count, bypass locking, and use the same lane concurrently. BTT lanes are also held across arena_write_bytes() calls. That path reaches nsio_rw_bytes(), which flushes writes with nvdimm_flush(). Some provider flush callbacks can sleep, making a spinlock the wrong primitive for the lane lifetime. Replace the spinlock-based recursion model with a dynamically allocated per-lane mutex array and take the lane lock unconditionally. Add might_sleep() to catch any future atomic-context caller. Found with the ndctl unit test btt-check.sh.
Impacted products
Vendor Product Version
Linux Linux Version: f23859748e3d530217b197e146a9ac84faf0a282
Version: 6f50b414f1a0d790f11a6438a3ad6d0577eb2c18
Version: 36c75ce3bd299878fd9b238e9803d3817ddafbf3
Version: 36c75ce3bd299878fd9b238e9803d3817ddafbf3
Version: 36c75ce3bd299878fd9b238e9803d3817ddafbf3
Version: 36c75ce3bd299878fd9b238e9803d3817ddafbf3
Version: 2577fece583c7c05cda7ad50dde7638c962665e1
Version: 40ba3fa21250e361bdd8f00800b3e2cb6160de95
Version: b0e7a935739f33ed2bd6868b89f97dd4c2683c26
Version: 66eb7b7f23dd9aec5356e7054dd3596ae7648ff5
Version: b27751fb1f271bbb78d5993c0b10011628e40e18
Version: 6.1.63   
Version: 6.6.2   
Version: 4.19.299   
Version: 5.4.261   
Version: 5.10.201   
Version: 5.15.139   
Version: 6.5.12   
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvdimm/btt: Handle preemption in BTT lane acquisition\n\nBTT lanes serialize access to per-lane metadata and workspace state\nduring BTT I/O. The btt-check unit test reports data mismatches during\nBTT writes due to a race in lane acquisition that can lead to silent\ndata corruption.\n\nThe existing lane model uses a spinlock together with a per-CPU\nrecursion count. That recursion model stopped being valid after BTT\nlanes became preemptible: another task can run on the same CPU,\nobserve a non-zero recursion count, bypass locking, and use the same\nlane concurrently.\n\nBTT lanes are also held across arena_write_bytes() calls. That path\nreaches nsio_rw_bytes(), which flushes writes with nvdimm_flush().\nSome provider flush callbacks can sleep, making a spinlock the wrong\nprimitive for the lane lifetime.\n\nReplace the spinlock-based recursion model with a dynamically\nallocated per-lane mutex array and take the lane lock\nunconditionally.\n\nAdd might_sleep() to catch any future atomic-context caller.\n\nFound with the ndctl unit test btt-check.sh."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The flaw is reached only through local block I/O on a BTT-backed /dev/pmem* device via vfs_write/pwrite/O_DIRECT paths into btt_submit_bio-\u003ebtt_write_pg/btt_read_pg-\u003end_region_acquire_lane; it is not in a network protocol handler.\nAC:L - After BTT lanes became preemptible, a second task on the same CPU can bypass the per-CPU recursion spinlock while the first still holds the lane across sleeping arena_write_bytes/nvdimm_flush; an attacker reliably wins by issuing concurrent writes (e.g., many threads) to the BTT block device.\nPR:L - No capability checks exist on the bio submission path; any local principal with write access to the BTT block device or a filesystem mounted on it (common for database/service accounts on PMEM servers) can trigger the race without real init-namespace root.\nUI:N - Exploitation requires only automated concurrent block writes from the attacker-controlled process and does not depend on any victim user opening files, clicking prompts, or performing other interactive actions.\nS:U - Impact is confined to corrupting BTT metadata and data within the attacker\u0027s reachable persistent-memory namespace on the same host; it does not cross VM, container, or IOMMU security boundaries to affect other security authorities.\nC:H - Unserialized lane use corrupts BTT map/log/freelist and in-memory arena-\u003ertt/freelist state, so reads can return stale or mis-mapped sector contents (cross-LBA disclosure); the ndctl btt-check test observed data mismatches confirming readable integrity loss.\nI:H - Concurrent writers can silently corrupt on-media BTT translation tables and user data blocks, producing arbitrary persistent storage modification rather than a bounded or detectable single-field change, matching the fix commit\u0027s silent data-corruption description.\nA:L - The primary failure mode is silent corruption and subsequent I/O errors on the affected namespace rather than a kernel panic or hang, but corrupted BTT metadata can persistently degrade or deny reliable access to the volume until recovery or rebuild."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:46:24.251Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fd7a97b2514cfc4b4cc067a27dd39bde2a8b1735"
        },
        {
          "url": "https://git.kernel.org/stable/c/73e35c1bdfa160b41fdbe204e02325f0687de506"
        },
        {
          "url": "https://git.kernel.org/stable/c/417918783bcfe0be135019df16a267b3af442efd"
        },
        {
          "url": "https://git.kernel.org/stable/c/5c53406098b599c420b031e6ec5ba8a2f3794c50"
        },
        {
          "url": "https://git.kernel.org/stable/c/4eafa810b042d985ec6bbf5b514414e73cee6f6f"
        },
        {
          "url": "https://git.kernel.org/stable/c/8d4b989d9c9afe5f185aa5853b666fc4617afe9e"
        }
      ],
      "title": "nvdimm/btt: Handle preemption in BTT lane acquisition",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74365",
    "datePublished": "2026-08-15T05:58:47.594Z",
    "dateReserved": "2026-08-15T05:44:03.888Z",
    "dateUpdated": "2026-08-17T05:46:24.251Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
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