CVE-2026-89459

/// Technical description

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

s390/percpu: Fix MVIY_PERCPU() with older binutils

Commit a737737cdb9c ("s390/percpu: Infrastructure for more efficient

this_cpu operations") introduced MVIY_PERCPU(), which stringifies

arguments that are already C string literals. This generates an

assembler macro invocation with whitespace-separated quoted arguments:

GEN_MVIY "459712" "%r3"

GNU as versions prior to binutils 2.39 drop the separating whitespace

between quoted macro arguments during input scrubbing. They

consequently parse the invocation as a single argument and emit

repeated warnings:

Warning: missing closing `"'

The .ifc in GEN_MVIY never matches and GNU as exits successfully

without emitting the mviy instruction. As a result, the interrupted

per-CPU sequence is not marked in lowcore and the exception return

path cannot repair the per-CPU address register after migration.

All MVIY_PERCPU() callers pass C string literals. Use them directly

a

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References