GHSA-9X8G-P3W8-2V5P

Vulnerability from github – Published: 2026-06-03 18:33 – Updated: 2026-06-05 09:33
VLAI
Details

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

MIPS: Work around LLVM bug when gp is used as global register variable

On MIPS, __current_thread_info is defined as global register variable locating in $gp, and is simply assigned with new address during kernel relocation.

This however is broken with LLVM, which always restores $gp if it finds $gp is clobbered in any form, including when intentionally through a global register variable. This is against GCC's documentation[1], which requires a callee-saved register used as global register variable not to be restored if it's clobbered.

As a result, $gp will continue to point to the unrelocated kernel after the epilog of relocate_kernel(), leading to an early crash in init_idle,

[ 0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000000000000000, epc == ffffffff81afada8, ra == ffffffff81afad90 [ 0.000000] Oops[#1]: [ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Tainted: G W 6.19.0-rc5-00262-gd3eeb99bbc99-dirty #188 VOLUNTARY [ 0.000000] Tainted: [W]=WARN [ 0.000000] Hardware name: loongson,loongson64v-4core-virtio [ 0.000000] $ 0 : 0000000000000000 0000000000000000 0000000000000001 0000000000000000 [ 0.000000] $ 4 : ffffffff80b80ec0 ffffffff80b53d48 0000000000000000 00000000000f4240 [ 0.000000] $ 8 : 0000000000000100 ffffffff81d82f80 ffffffff81d82f80 0000000000000001 [ 0.000000] $12 : 0000000000000000 ffffffff81776f58 00000000000005da 0000000000000002 [ 0.000000] $16 : ffffffff80b80e40 0000000000000000 ffffffff80b81614 9800000005dfbe80 [ 0.000000] $20 : 00000000540000e0 ffffffff81980000 0000000000000000 ffffffff80f81c80 [ 0.000000] $24 : 0000000000000a26 ffffffff8114fb90 [ 0.000000] $28 : ffffffff80b50000 ffffffff80b53d40 0000000000000000 ffffffff81afad90 [ 0.000000] Hi : 0000000000000000 [ 0.000000] Lo : 0000000000000000 [ 0.000000] epc : ffffffff81afada8 init_idle+0x130/0x270 [ 0.000000] ra : ffffffff81afad90 init_idle+0x118/0x270 [ 0.000000] Status: 540000e2 KX SX UX KERNEL EXL [ 0.000000] Cause : 00000008 (ExcCode 02) [ 0.000000] BadVA : 0000000000000000 [ 0.000000] PrId : 00006305 (ICT Loongson-3) [ 0.000000] Process swapper (pid: 0, threadinfo=(_ptrval), task=(_ptrval), tls=0000000000000000) [ 0.000000] Stack : 9800000005dfbf00 ffffffff8178e950 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 ffffffff81970000 000000000000003f ffffffff810a6528 [ 0.000000] 0000000000000001 9800000005dfbe80 9800000005dfbf00 ffffffff81980000 [ 0.000000] ffffffff810a6450 ffffffff81afb6c0 0000000000000000 ffffffff810a2258 [ 0.000000] ffffffff81d82ec8 ffffffff8198d010 ffffffff81b67e80 ffffffff8197dd98 [ 0.000000] ffffffff81d81c80 ffffffff81930000 0000000000000040 0000000000000000 [ 0.000000] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 000000000000009e ffffffff9fc01000 0000000000000000 [ 0.000000] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 ffffffff81ae86dc ffffffff81b3c741 0000000000000002 [ 0.000000] ... [ 0.000000] Call Trace: [ 0.000000] [] init_idle+0x130/0x270 [ 0.000000] [] sched_init+0x5c8/0x6c0 [ 0.000000] [] start_kernel+0x27c/0x7a8

This bug has been reported to LLVM[2] and affects version from (at least) 18 to 21. Let's work around this by using inline assembly to assign $gp before a fix is widely available.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-46250"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-03T18:16:25Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nMIPS: Work around LLVM bug when gp is used as global register variable\n\nOn MIPS, __current_thread_info is defined as global register variable\nlocating in $gp, and is simply assigned with new address during kernel\nrelocation.\n\nThis however is broken with LLVM, which always restores $gp if it finds\n$gp is clobbered in any form, including when intentionally through a\nglobal register variable. This is against GCC\u0027s documentation[1], which\nrequires a callee-saved register used as global register variable not to\nbe restored if it\u0027s clobbered.\n\nAs a result, $gp will continue to point to the unrelocated kernel after\nthe epilog of relocate_kernel(), leading to an early crash in init_idle,\n\n[    0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000000000000000, epc == ffffffff81afada8, ra == ffffffff81afad90\n[    0.000000] Oops[#1]:\n[    0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Tainted: G        W           6.19.0-rc5-00262-gd3eeb99bbc99-dirty #188 VOLUNTARY\n[    0.000000] Tainted: [W]=WARN\n[    0.000000] Hardware name: loongson,loongson64v-4core-virtio\n[    0.000000] $ 0   : 0000000000000000 0000000000000000 0000000000000001 0000000000000000\n[    0.000000] $ 4   : ffffffff80b80ec0 ffffffff80b53d48 0000000000000000 00000000000f4240\n[    0.000000] $ 8   : 0000000000000100 ffffffff81d82f80 ffffffff81d82f80 0000000000000001\n[    0.000000] $12   : 0000000000000000 ffffffff81776f58 00000000000005da 0000000000000002\n[    0.000000] $16   : ffffffff80b80e40 0000000000000000 ffffffff80b81614 9800000005dfbe80\n[    0.000000] $20   : 00000000540000e0 ffffffff81980000 0000000000000000 ffffffff80f81c80\n[    0.000000] $24   : 0000000000000a26 ffffffff8114fb90\n[    0.000000] $28   : ffffffff80b50000 ffffffff80b53d40 0000000000000000 ffffffff81afad90\n[    0.000000] Hi    : 0000000000000000\n[    0.000000] Lo    : 0000000000000000\n[    0.000000] epc   : ffffffff81afada8 init_idle+0x130/0x270\n[    0.000000] ra    : ffffffff81afad90 init_idle+0x118/0x270\n[    0.000000] Status: 540000e2\tKX SX UX KERNEL EXL\n[    0.000000] Cause : 00000008 (ExcCode 02)\n[    0.000000] BadVA : 0000000000000000\n[    0.000000] PrId  : 00006305 (ICT Loongson-3)\n[    0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000)\n[    0.000000] Stack : 9800000005dfbf00 ffffffff8178e950 0000000000000000 0000000000000000\n[    0.000000]         0000000000000000 ffffffff81970000 000000000000003f ffffffff810a6528\n[    0.000000]         0000000000000001 9800000005dfbe80 9800000005dfbf00 ffffffff81980000\n[    0.000000]         ffffffff810a6450 ffffffff81afb6c0 0000000000000000 ffffffff810a2258\n[    0.000000]         ffffffff81d82ec8 ffffffff8198d010 ffffffff81b67e80 ffffffff8197dd98\n[    0.000000]         ffffffff81d81c80 ffffffff81930000 0000000000000040 0000000000000000\n[    0.000000]         0000000000000000 0000000000000000 0000000000000000 0000000000000000\n[    0.000000]         0000000000000000 000000000000009e ffffffff9fc01000 0000000000000000\n[    0.000000]         0000000000000000 0000000000000000 0000000000000000 0000000000000000\n[    0.000000]         0000000000000000 ffffffff81ae86dc ffffffff81b3c741 0000000000000002\n[    0.000000]         ...\n[    0.000000] Call Trace:\n[    0.000000] [\u003cffffffff81afada8\u003e] init_idle+0x130/0x270\n[    0.000000] [\u003cffffffff81afb6c0\u003e] sched_init+0x5c8/0x6c0\n[    0.000000] [\u003cffffffff81ae86dc\u003e] start_kernel+0x27c/0x7a8\n\nThis bug has been reported to LLVM[2] and affects version from (at\nleast) 18 to 21. Let\u0027s work around this by using inline assembly to\nassign $gp before a fix is widely available.",
  "id": "GHSA-9x8g-p3w8-2v5p",
  "modified": "2026-06-05T09:33:46Z",
  "published": "2026-06-03T18:33:12Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46250"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/05bff9b0ae095b2420cfebb4a96759a09334bec6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1fe3b402b1e97a1718df3be0a1d3eee20133e735"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/30bfc2d6a1132a89a5f1c3b96c59cf3e4d076ea3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4dc65b40fb80c2020efbf139b9a38d30f9a37b92"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/561834f6d6f52b8a1791331e94b2aac753491d2a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9bc3b0ae5203aba650297fdf3e1e774125e423f2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c0155dee51b9f5f48aaf5c71cae005eb0e36521f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e3a6498a63394218561065a9a7a597a204f52f6a"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
      "type": "CVSS_V3"
    }
  ]
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Loading…

Detection rules are retrieved from Rulezet.

Loading…

Loading…