FKIE_CVE-2025-71102

Vulnerability from fkie_nvd - Published: 2026-01-14 15:15 - Updated: 2026-01-19 13:16
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: scs: fix a wrong parameter in __scs_magic __scs_magic() needs a 'void *' variable, but a 'struct task_struct *' is given. 'task_scs(tsk)' is the starting address of the task's shadow call stack, and '__scs_magic(task_scs(tsk))' is the end address of the task's shadow call stack. Here should be '__scs_magic(task_scs(tsk))'. The user-visible effect of this bug is that when CONFIG_DEBUG_STACK_USAGE is enabled, the shadow call stack usage checking function (scs_check_usage) would scan an incorrect memory range. This could lead 1. **Inaccurate stack usage reporting**: The function would calculate wrong usage statistics for the shadow call stack, potentially showing incorrect value in kmsg. 2. **Potential kernel crash**: If the value of __scs_magic(tsk)is greater than that of __scs_magic(task_scs(tsk)), the for loop may access unmapped memory, potentially causing a kernel panic. However, this scenario is unlikely because task_struct is allocated via the slab allocator (which typically returns lower addresses), while the shadow call stack returned by task_scs(tsk) is allocated via vmalloc(which typically returns higher addresses). However, since this is purely a debugging feature (CONFIG_DEBUG_STACK_USAGE), normal production systems should be not unaffected. The bug only impacts developers and testers who are actively debugging stack usage with this configuration enabled.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/062774439d442882b44f5eab8c256ad3423ef284
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/08bd4c46d5e63b78e77f2605283874bbe868ab19
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1727e8bd69103a68963a5613a0ddb6d8d37df5d3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/57ba40b001be27786d0570dd292289df748b306b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9ef28943471a16e4f9646bc3e8e2de148e7d8d7b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a19fb3611e4c06624fc0f83ef19f4fb8d57d4751
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cfdf6250b63b953b1d8e60814c8ca96c6f9d1c8c
Impacted products
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscs: fix a wrong parameter in __scs_magic\n\n__scs_magic() needs a \u0027void *\u0027 variable, but a \u0027struct task_struct *\u0027 is\ngiven.  \u0027task_scs(tsk)\u0027 is the starting address of the task\u0027s shadow call\nstack, and \u0027__scs_magic(task_scs(tsk))\u0027 is the end address of the task\u0027s\nshadow call stack.  Here should be \u0027__scs_magic(task_scs(tsk))\u0027.\n\nThe user-visible effect of this bug is that when CONFIG_DEBUG_STACK_USAGE\nis enabled, the shadow call stack usage checking function\n(scs_check_usage) would scan an incorrect memory range.  This could lead\n\n1. **Inaccurate stack usage reporting**: The function would calculate\n   wrong usage statistics for the shadow call stack, potentially showing\n   incorrect value in kmsg.\n\n2. **Potential kernel crash**: If the value of __scs_magic(tsk)is\n   greater than that of __scs_magic(task_scs(tsk)), the for loop may\n   access unmapped memory, potentially causing a kernel panic.  However,\n   this scenario is unlikely because task_struct is allocated via the slab\n   allocator (which typically returns lower addresses), while the shadow\n   call stack returned by task_scs(tsk) is allocated via vmalloc(which\n   typically returns higher addresses).\n\nHowever, since this is purely a debugging feature\n(CONFIG_DEBUG_STACK_USAGE), normal production systems should be not\nunaffected.  The bug only impacts developers and testers who are actively\ndebugging stack usage with this configuration enabled."
    }
  ],
  "id": "CVE-2025-71102",
  "lastModified": "2026-01-19T13:16:17.857",
  "metrics": {},
  "published": "2026-01-14T15:15:59.210",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/062774439d442882b44f5eab8c256ad3423ef284"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/08bd4c46d5e63b78e77f2605283874bbe868ab19"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1727e8bd69103a68963a5613a0ddb6d8d37df5d3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/57ba40b001be27786d0570dd292289df748b306b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9ef28943471a16e4f9646bc3e8e2de148e7d8d7b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a19fb3611e4c06624fc0f83ef19f4fb8d57d4751"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cfdf6250b63b953b1d8e60814c8ca96c6f9d1c8c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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