lib: test_hmm: evict device pages on file close to avoid use-after-free

{
  "id": "51386981a4eb64c98f844aed05810097e2228808e6c57252010695338f473888",
  "url": "https://osv.dev/vulnerability/CVE-2026-46280",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "lib: test_hmm: evict device pages on file close to avoid use-after-free",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: lib: test_hmm: evict device pages on file close to avoid use-after-free Patch series \"Minor hmm_test fixes and cleanups\". Two bugfixes a cleanup for the HMM kernel selftests. These were mostly reported by Zenghui Yu with special thanks to Lorenzo for analysing and pointing out the problems. This patch (of 3): When dmirror_fops_release() is called it frees the dmirror struct but doesn't migrate device private pages back to system memory first. This leaves those pages with a dangling zone_device_data pointer to the freed dmirror. If a subsequent fault occurs on those pages (eg. during coredump) the dmirror_devmem_fault() callback dereferences the stale pointer causing a kernel panic. This was reported [1] when running mm/ksft_hmm.sh on arm64, where a test failure triggered SIGABRT and the resulting coredump walked the VMAs faulting in the stale device private pages. Fix this by calling dmirror_device_evict_chunk() for each devmem chunk in dmirror_fops_release() to migrate all device private pages back to system memory before freeing the dmirror struct. The function is moved earlier in the file to avoid a forward declaration.",
    "evidence": "osv:CVE-2026-46280",
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      "modified": "2026-10-28T02:30:37.654162382Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/234071b4318feaeb27cd2e4e1b16ef6b055adf89",
        "https://git.kernel.org/stable/c/38f113f81d3f0adc658a4475dd3ecaec985e21d3",
        "https://git.kernel.org/stable/c/5846715b6382dd4c6a69b35a56ca6115d33bc2a0",
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        "https://git.kernel.org/stable/c/bf477abd448c76bb8ea51c9b4f63a3a17c4b6239",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46280.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-46280",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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  "source_id": "core-osv",
  "document_id": 504986,
  "published_at": "2026-06-08T15:41:23.095+00:00"
}