MIPS: Work around LLVM bug when gp is used as global register variable_CVE-2026-46250

{
    "lastseen": "",
    "description": "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's documentation[1], which\nrequires a callee-saved register used as global register variable not to\nbe restored if it's 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] [<ffffffff81afada8>] init_idle+0x130/0x270\n[    0.000000] [<ffffffff81afb6c0>] sched_init+0x5c8/0x6c0\n[    0.000000] [<ffffffff81ae86dc>] start_kernel+0x27c/0x7a8\n\nThis bug has been reported to LLVM[2] and affects version from (at\nleast) 18 to 21. Let's work around this by using inline assembly to\nassign $gp before a fix is widely available.",
    "published": "2026-06-03T15:49:46.390Z",
    "modified": "2026-06-05T06:06:21.916Z",
    "type": "cve",
    "title": "MIPS: Work around LLVM bug when gp is used as global register variable",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/05bff9b0ae095b2420cfebb4a96759a09334bec6\nhttps://git.kernel.org/stable/c/1fe3b402b1e97a1718df3be0a1d3eee20133e735\nhttps://git.kernel.org/stable/c/4dc65b40fb80c2020efbf139b9a38d30f9a37b92\nhttps://git.kernel.org/stable/c/c0155dee51b9f5f48aaf5c71cae005eb0e36521f\nhttps://git.kernel.org/stable/c/e3a6498a63394218561065a9a7a597a204f52f6a\nhttps://git.kernel.org/stable/c/561834f6d6f52b8a1791331e94b2aac753491d2a\nhttps://git.kernel.org/stable/c/9bc3b0ae5203aba650297fdf3e1e774125e423f2\nhttps://git.kernel.org/stable/c/30bfc2d6a1132a89a5f1c3b96c59cf3e4d076ea3",
    "id": "CVE-2026-46250",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\nLinux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\nLinux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\nLinux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\nLinux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\nLinux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\nLinux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\nLinux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\nLinux Linux 0\nLinux Linux 0\nLinux Linux 0\nLinux Linux 0\nLinux Linux 0\nLinux Linux 0\nLinux Linux 0",
    "sourceHref": "",
    "cvss": {
        "score": 7.3,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
        "version": "3.1"
    },
    "cvss2": [],
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        "baseScore": 0,
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        "cvssV3": {
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    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
    "vendor": "Linux",
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    "ai_score": 0
}