GHSA-56RC-PFJ3-9MX3

Vulnerability from github – Published: 2025-12-04 18:30 – Updated: 2025-12-04 18:30
VLAI?
Details

In the Linux kernel, the following vulnerability has been resolved:

nios2: ensure that memblock.current_limit is set when setting pfn limits

On nios2, with CONFIG_FLATMEM set, the kernel relies on memblock_get_current_limit() to determine the limits of mem_map, in particular for max_low_pfn. Unfortunately, memblock.current_limit is only default initialized to MEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading to situations where max_low_pfn can erroneously exceed the value of max_pfn and, thus, the valid range of available DRAM.

This can in turn cause kernel-level paging failures, e.g.:

[ 76.900000] Unable to handle kernel paging request at virtual address 20303000 [ 76.900000] ea = c0080890, ra = c000462c, cause = 14 [ 76.900000] Kernel panic - not syncing: Oops [ 76.900000] ---[ end Kernel panic - not syncing: Oops ]---

This patch fixes this by pre-calculating memblock.current_limit based on the upper limits of the available memory ranges via adjust_lowmem_bounds, a simplified version of the equivalent implementation within the arm architecture.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-40245"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-04T16:16:17Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnios2: ensure that memblock.current_limit is set when setting pfn limits\n\nOn nios2, with CONFIG_FLATMEM set, the kernel relies on\nmemblock_get_current_limit() to determine the limits of mem_map, in\nparticular for max_low_pfn.\nUnfortunately, memblock.current_limit is only default initialized to\nMEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading\nto situations where max_low_pfn can erroneously exceed the value of\nmax_pfn and, thus, the valid range of available DRAM.\n\nThis can in turn cause kernel-level paging failures, e.g.:\n\n[   76.900000] Unable to handle kernel paging request at virtual address 20303000\n[   76.900000] ea = c0080890, ra = c000462c, cause = 14\n[   76.900000] Kernel panic - not syncing: Oops\n[   76.900000] ---[ end Kernel panic - not syncing: Oops ]---\n\nThis patch fixes this by pre-calculating memblock.current_limit\nbased on the upper limits of the available memory ranges via\nadjust_lowmem_bounds, a simplified version of the equivalent\nimplementation within the arm architecture.",
  "id": "GHSA-56rc-pfj3-9mx3",
  "modified": "2025-12-04T18:30:52Z",
  "published": "2025-12-04T18:30:52Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40245"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/25f09699edd360b534ccae16bc276c3b52c471f3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5c3e38a367822f036227dd52bac82dc4a05157e2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8912814f14e298b83df072fecc1f7ed1b63b1b2c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/90f5f715550e07cd6a51f80fc3f062d832c8c997"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a20b83cf45be2057f3d073506779e52c7fa17f94"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b1ec9faef7e36269ca3ec890972a78effbaeb975"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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