CVE-2025-68751

Technical Description

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

s390/fpu: Fix false-positive kmsan report in fpu_vstl()

A false-positive kmsan report is detected when running ping command.

An inline assembly instruction 'vstl' can write varied amount of bytes

depending on value of 'index' argument. If 'index' > 0, 'vstl' writes

at least 2 bytes.

clang generates kmsan write helper call depending on inline assembly

constraints. Constraints are evaluated compile-time, but value of

'index' argument is known only at runtime.

clang currently generates call to __msan_instrument_asm_store with 1 byte

as size. Manually call kmsan function to indicate correct amount of bytes

written and fix false-positive report.

This change fixes following kmsan reports:

[ 36.563119] =====================================================

[ 36.563594] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70

[ 36.563852] virtqueue_add+0x35c6/0x7c70

[ 36.564016] virtqueue_add_outbuf+0xa0/0xb0

[

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