ghsa-v3gm-f9gf-wg97
Vulnerability from github
Published
2025-10-14 21:30
Modified
2025-10-14 21:30
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

highmem: fix checks in __kmap_local_sched_{in,out}

When CONFIG_DEBUG_KMAP_LOCAL is enabled __kmap_local_sched_{in,out} check that even slots in the tsk->kmap_ctrl.pteval are unmapped. The slots are initialized with 0 value, but the check is done with pte_none. 0 pte however does not necessarily mean that pte_none will return true. e.g. on xtensa it returns false, resulting in the following runtime warnings:

WARNING: CPU: 0 PID: 101 at mm/highmem.c:627 __kmap_local_sched_out+0x51/0x108 CPU: 0 PID: 101 Comm: touch Not tainted 5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13 Call Trace: dump_stack+0xc/0x40 __warn+0x8f/0x174 warn_slowpath_fmt+0x48/0xac __kmap_local_sched_out+0x51/0x108 __schedule+0x71a/0x9c4 preempt_schedule_irq+0xa0/0xe0 common_exception_return+0x5c/0x93 do_wp_page+0x30e/0x330 handle_mm_fault+0xa70/0xc3c do_page_fault+0x1d8/0x3c4 common_exception+0x7f/0x7f

WARNING: CPU: 0 PID: 101 at mm/highmem.c:664 __kmap_local_sched_in+0x50/0xe0 CPU: 0 PID: 101 Comm: touch Tainted: G W 5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13 Call Trace: dump_stack+0xc/0x40 __warn+0x8f/0x174 warn_slowpath_fmt+0x48/0xac __kmap_local_sched_in+0x50/0xe0 finish_task_switch$isra$0+0x1ce/0x2f8 __schedule+0x86e/0x9c4 preempt_schedule_irq+0xa0/0xe0 common_exception_return+0x5c/0x93 do_wp_page+0x30e/0x330 handle_mm_fault+0xa70/0xc3c do_page_fault+0x1d8/0x3c4 common_exception+0x7f/0x7f

Fix it by replacing !pte_none(pteval) with pte_val(pteval) != 0.

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{
  "affected": [],
  "aliases": [
    "CVE-2022-49081"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-26T07:00:45Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nhighmem: fix checks in __kmap_local_sched_{in,out}\n\nWhen CONFIG_DEBUG_KMAP_LOCAL is enabled __kmap_local_sched_{in,out} check\nthat even slots in the tsk-\u003ekmap_ctrl.pteval are unmapped.  The slots are\ninitialized with 0 value, but the check is done with pte_none.  0 pte\nhowever does not necessarily mean that pte_none will return true.  e.g.\non xtensa it returns false, resulting in the following runtime warnings:\n\n WARNING: CPU: 0 PID: 101 at mm/highmem.c:627 __kmap_local_sched_out+0x51/0x108\n CPU: 0 PID: 101 Comm: touch Not tainted 5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13\n Call Trace:\n   dump_stack+0xc/0x40\n   __warn+0x8f/0x174\n   warn_slowpath_fmt+0x48/0xac\n   __kmap_local_sched_out+0x51/0x108\n   __schedule+0x71a/0x9c4\n   preempt_schedule_irq+0xa0/0xe0\n   common_exception_return+0x5c/0x93\n   do_wp_page+0x30e/0x330\n   handle_mm_fault+0xa70/0xc3c\n   do_page_fault+0x1d8/0x3c4\n   common_exception+0x7f/0x7f\n\n WARNING: CPU: 0 PID: 101 at mm/highmem.c:664 __kmap_local_sched_in+0x50/0xe0\n CPU: 0 PID: 101 Comm: touch Tainted: G        W         5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13\n Call Trace:\n   dump_stack+0xc/0x40\n   __warn+0x8f/0x174\n   warn_slowpath_fmt+0x48/0xac\n   __kmap_local_sched_in+0x50/0xe0\n   finish_task_switch$isra$0+0x1ce/0x2f8\n   __schedule+0x86e/0x9c4\n   preempt_schedule_irq+0xa0/0xe0\n   common_exception_return+0x5c/0x93\n   do_wp_page+0x30e/0x330\n   handle_mm_fault+0xa70/0xc3c\n   do_page_fault+0x1d8/0x3c4\n   common_exception+0x7f/0x7f\n\nFix it by replacing !pte_none(pteval) with pte_val(pteval) != 0.",
  "id": "GHSA-v3gm-f9gf-wg97",
  "modified": "2025-10-14T21:30:25Z",
  "published": "2025-10-14T21:30:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49081"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/66f133ceab7456c789f70a242991ed1b27ba1c3d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7dd5b3b97716a611fcf67d92fd2370fcb8d50372"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/85550b0f5fa5dd3c30469ea702c44444ef242c83"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c21d040de6225414547d9bd31cd200f290991c85"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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