{"id":"CVE-2026-98228","summary":"mips: select CONFIG_WEAK_REORDERING_BEYOND_LLSC from CONFIG_EYEQ","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmips: select CONFIG_WEAK_REORDERING_BEYOND_LLSC from CONFIG_EYEQ\n\nOn I6500 CPU cores, lld and scd give no ordering guarantees (same as all\nother instructions). To respect the assumption that arch_cmpxchg() is\nfully ordered, we must inject sync instructions above and below our\nlld/scd loops using the already in place WEAK_REORDERING_BEYOND_LLSC\ninfrastructure.\n\nOtherwise, bad things can happen:\n\n[   34.054496] CPU 3 Unable to handle kernel paging request at virtual address 0000000000000000, epc == a80000080838e01c, ra == a80000080838dfc4\n[   34.054559] Oops[#1]:\n[   34.069561] CPU: 3 UID: 0 PID: 170 Comm: pipe_race Not tainted 7.2.0-rc6-01553-gb73c35220968-dirty #103 VOLUNTARY\n[   34.079932] Hardware name: Mobile EyeQ5 MP5 Evaluation board\n[   34.085592] $ 0   : 0000000000000000 0000000000000001 0000000000000000 0000000000000000\n[   34.093616] $ 4   : a800000808ee2618 000000000b7a879d 0000000000001000 0000000000000000\n[   34.101638] $ 8   : 0000000000e3f2c9 0000000000000000 a800000808a2a9f8 0000000000000000\n[   34.109660] $12   : a8000008139ffcd8 ffffffff84080018 a80000080837fae0 7878787878787878\n[   34.117682] $16   : a800000807e82940 0000000000001000 0000000000000000 0000000000000000\n[   34.125704] $20   : a800000802920e00 a8000008139ffdf8 a800000802649400 0000000000e3f2c9\n[   34.133726] $24   : 0000000000000006 00000001200406e0\n[   34.141783] $28   : a8000008139fc000 a8000008139ffd10 0000000000e3f2c8 a80000080838dfc4\n[   34.149837] epc   : a80000080838e01c anon_pipe_read+0xd4/0x428\n[   34.155697] ra    : a80000080838dfc4 anon_pipe_read+0x7c/0x428\n[   34.161549] Status: 140000e3  KX SX UX KERNEL EXL IE\n[   34.166551] Cause : 40800408 (ExcCode 02)\n[   34.170574] BadVA : 0000000000000000\n[   34.174161] PrId  : 0001b028 (MIPS I6500)\n[   34.178183] Process pipe_race (pid: 170, threadinfo=000000005ca35720, task=00000000e1013890, tls=000000014ebbb780)\n[   34.188568] Stack : a800000802649400 0000000000000000 0000000000000000 a8000008139ffdd0\n[   34.196623]\t 0000000000000fba a800000808ee0000 0000000000000001 a8000008130c3e80\n[   34.204676]\t a8000008080d1280 a8000008139ffd58 a8000008139ffd58 1dbd2b22ea1dd500\n[   34.212729]\t a800000802649400 a800000808ee0000 ffffffffffffffea 0000000000000001\n[   34.220783]\t 0000000000001000 0000000000000000 00000001200ae518 ffffffffffffffff\n[   34.228836]\t 000000fffbe0e530 a80000080837edf4 000000fffbe0e530 0000000000000000\n[   34.236890]\t 0000000000000000 0000000000000000 000000014ebb55a0 0000000000001000\n[   34.244943]\t 0000000000000001 a800000802649400 0000000000000000 0000000000000000\n[   34.252996]\t 0000000000000000 0000400400000000 0000000000000000 1dbd2b22ea1dd500\n[   34.261049]\t 00000000140000e3 a800000802649400 a800000802649400 a800000808ee0000\n[   34.269103]\t ...\n[   34.271568] Call Trace:\n[   34.274026] [\u003ca80000080838e01c\u003e] anon_pipe_read+0xd4/0x428\n[   34.279533] [\u003ca80000080837edf4\u003e] vfs_read+0x25c/0x318\n[   34.284607] [\u003ca80000080837faac\u003e] ksys_read+0x104/0x138\n[   34.289763] [\u003ca80000080802b9cc\u003e] syscall_common+0x44/0x68\n[   34.295187]\n[   34.296689] Code: f84000cf  02209825  de020010 \u003cdc420000\u003e d8400004  02002825  0040f809  02802025  f84000c3\n[   34.306504]\n[   34.308099] ---[ end trace 0000000000000000 ]---\n\nMy initial reproducer was the xdp-tools test suite. A standalone\nreproducer would be an lld/scd loop that, when the read is reordered by\nthe CPU, triggers a fault. We can achieve this from userspace by\nstressing an anonymous pipe, which uses a mutex. Program used:\n\n\t// SPDX-License-Identifier: GPL-2.0\n\t// pipe_race.c - reproducer for MIPS LL/SC reordering vs fs/pipe.c\n\t//\n\t// Two userspace processes on an anonymous pipe:\n\t//   parent  = writer: tight write() loop\n\t//   child   = reader: tight read() loop\n\n\t#define _GNU_SOURCE\n\t#include \u003cassert.h\u003e\n\t#include \u003cerrno.h\u003e\n\t#include \u003csched.h\u003e\n\t#include \u003csignal.h\u003e\n\t#include \u003cstdio.h\u003e\n\t#include \u003cstdlib.h\u003e\n\t#include \u003cstring.h\u003e\n\t#include \u003csys/types.h\u003e\n\t#include\n---truncated---","modified":"2026-10-08T02:52:54.950315595Z","published":"2026-10-06T08:45:03.154Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98228.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3f017c2ca8c31a1e135dd87be647096866d6b196"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bbc448c541ed90d52f9ec22f17394304e3bf170e"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98228.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98228"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fbe0fae601b780622fcb7034a479fa161645b9f4"},{"fixed":"3f017c2ca8c31a1e135dd87be647096866d6b196"},{"fixed":"bbc448c541ed90d52f9ec22f17394304e3bf170e"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98228.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.11.0"},{"fixed":"7.2.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98228.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}