---
id: CVE-2026-99092
title: 'riscv: patch: fix handling of bpf-jit execmem addresses'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  riscv: patch: fix handling of bpf-jit execmem addresses

  Commit 8718e5a3090b ("riscv: patch: skip fixmap mapping when kernel text
  is already writable") gated the core_k…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 2c9e5d4a008293407836d29d35dfd4353615bd2f <
    562a35b9e0b3d9483d9472995219cadb3592db3d
  - >-
    Linux >= 2c9e5d4a008293407836d29d35dfd4353615bd2f <
    9e8fc7972b398e9dc2415ece283d8f64edac3858
  - >-
    Linux >= 2c9e5d4a008293407836d29d35dfd4353615bd2f <
    f71d6ea3843c8038c431c2699482f246aea37ca0
  - >-
    Linux >= 2c9e5d4a008293407836d29d35dfd4353615bd2f <
    a510e1ae8c9030750c2edf7b0bc9b186cd8c7a06
  - Linux 6.10
published: '2026-10-26'
updated: '2026-10-26'
sourceUpdated: '2026-10-26T14:52:00.860Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-99092'
references:
  - url: 'https://git.kernel.org/stable/c/562a35b9e0b3d9483d9472995219cadb3592db3d'
  - url: 'https://git.kernel.org/stable/c/9e8fc7972b398e9dc2415ece283d8f64edac3858'
  - url: 'https://git.kernel.org/stable/c/f71d6ea3843c8038c431c2699482f246aea37ca0'
  - url: 'https://git.kernel.org/stable/c/a510e1ae8c9030750c2edf7b0bc9b186cd8c7a06'
tags:
  - cve.org
ingestedAt: '2026-10-26T15:29:30.510Z'
---

## Overview

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

riscv: patch: fix handling of bpf-jit execmem addresses

Commit 8718e5a3090b ("riscv: patch: skip fixmap mapping when kernel text
is already writable") gated the core_kernel_text() branch of patch_map()
on CONFIG_STRICT_KERNEL_RWX, and explicitly left the vmalloc branch
unchanged. That branch has a separate problem.

That branch only creates a temporary writable fixmap alias when
CONFIG_STRICT_MODULE_RWX is enabled, and otherwise assumes the target is
directly writable and returns the address unchanged. That assumption no
longer holds: bpf_prog_pack_alloc calls set_memory_rox() on every pack
unconditionally in alloc_new_pack(), independently of any
CONFIG_STRICT_*_RWX option, so BPF text in the vmalloc area is read-only
regardless of what CONFIG_STRICT_MODULE_RWX says.

With CONFIG_STRICT_MODULE_RWX=n, patch_map() returns the read-only
address directly, the subsequent copy_to_kernel_nofault() takes a
page fault and returns -EFAULT. bpf_arch_text_copy() turns that into
-EINVAL, which propagates through bpf_jit_binary_pack_finalize() to the
WARN_ON() in bpf_int_jit_compile() and leaves the program un-JITed.

Note that BPF cannot be fixed the way kprobes was in
commit bdc46e507b59 ("riscv: mm: make EXECMEM_KPROBES writable without
CONFIG_STRICT_MODULE_RWX"). EXECMEM_BPF is already PAGE_KERNEL, i.e.
writable at allocation time; the read-only mapping is established
afterwards by generic code in alloc_new_pack(), which arch code cannot
influence. The only place this can be handled is patch_map().

This is the same problem that was fixed on arm64 by commit b1480ed230ac
("arm64: patching: fix handling of execmem addresses"), and the fix is
the same: CONFIG_EXECMEM is what actually tracks whether the vmalloc
area can hold executable memory that needs a temporary alias to be
written. CONFIG_BPF_JIT, CONFIG_KPROBES and CONFIG_MODULES all select
it.

Note that this is not limited to CONFIG_MODULES=n. Unlike arm64, riscv
selects CONFIG_ARCH_OPTIONAL_KERNEL_RWX, so CONFIG_STRICT_MODULE_RWX can
be disabled with CONFIG_MODULES=y as well, and the bug is reachable in
that configuration too.

The !CONFIG_MMU build is unaffected: it has its own __patch_insn_set()
and __patch_insn_write() implementations and never calls patch_map().

## Affected

- `Linux >= 2c9e5d4a008293407836d29d35dfd4353615bd2f < 562a35b9e0b3d9483d9472995219cadb3592db3d`
- `Linux >= 2c9e5d4a008293407836d29d35dfd4353615bd2f < 9e8fc7972b398e9dc2415ece283d8f64edac3858`
- `Linux >= 2c9e5d4a008293407836d29d35dfd4353615bd2f < f71d6ea3843c8038c431c2699482f246aea37ca0`
- `Linux >= 2c9e5d4a008293407836d29d35dfd4353615bd2f < a510e1ae8c9030750c2edf7b0bc9b186cd8c7a06`
- `Linux 6.10`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.