fkie_cve-2025-39725
Vulnerability from fkie_nvd
Published
2025-09-05 18:15
Modified
2025-09-08 16:25
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list In shrink_folio_list(), the hwpoisoned folio may be large folio, which can't be handled by unmap_poisoned_folio(). For THP, try_to_unmap_one() must be passed with TTU_SPLIT_HUGE_PMD to split huge PMD first and then retry. Without TTU_SPLIT_HUGE_PMD, we will trigger null-ptr deref of pvmw.pte. Even we passed TTU_SPLIT_HUGE_PMD, we will trigger a WARN_ON_ONCE due to the page isn't in swapcache. Since UCE is rare in real world, and race with reclaimation is more rare, just skipping the hwpoisoned large folio is enough. memory_failure() will handle it if the UCE is triggered again. This happens when memory reclaim for large folio races with memory_failure(), and will lead to kernel panic. The race is as follows: cpu0 cpu1 shrink_folio_list memory_failure TestSetPageHWPoison unmap_poisoned_folio --> trigger BUG_ON due to unmap_poisoned_folio couldn't handle large folio [tujinjiang@huawei.com: add comment to unmap_poisoned_folio()]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/656eaddbc952e1baae2f69281c22debe22140312
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9f1e8cd0b7c4c944e9921b52a6661b5eda2705ab
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c1101113d45838a823188ae25c61af97552a28ae
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list\n\nIn shrink_folio_list(), the hwpoisoned folio may be large folio, which\ncan\u0027t be handled by unmap_poisoned_folio().  For THP, try_to_unmap_one()\nmust be passed with TTU_SPLIT_HUGE_PMD to split huge PMD first and then\nretry.  Without TTU_SPLIT_HUGE_PMD, we will trigger null-ptr deref of\npvmw.pte.  Even we passed TTU_SPLIT_HUGE_PMD, we will trigger a\nWARN_ON_ONCE due to the page isn\u0027t in swapcache.\n\nSince UCE is rare in real world, and race with reclaimation is more rare,\njust skipping the hwpoisoned large folio is enough.  memory_failure() will\nhandle it if the UCE is triggered again.\n\nThis happens when memory reclaim for large folio races with\nmemory_failure(), and will lead to kernel panic.  The race is as\nfollows:\n\ncpu0      cpu1\n shrink_folio_list memory_failure\n  TestSetPageHWPoison\n  unmap_poisoned_folio\n  --\u003e trigger BUG_ON due to\n  unmap_poisoned_folio couldn\u0027t\n   handle large folio\n\n[tujinjiang@huawei.com: add comment to unmap_poisoned_folio()]"
    }
  ],
  "id": "CVE-2025-39725",
  "lastModified": "2025-09-08T16:25:38.810",
  "metrics": {},
  "published": "2025-09-05T18:15:50.320",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/656eaddbc952e1baae2f69281c22debe22140312"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9f1e8cd0b7c4c944e9921b52a6661b5eda2705ab"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c1101113d45838a823188ae25c61af97552a28ae"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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