linux-cve-announce - CVE-2025-71115: um: init cpu

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Message-ID: <2026011414-CVE-2025-71115-7c28@gregkh>
Date: Wed, 14 Jan 2026 16:06:20 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-71115: um: init cpu_tasks[] earlier

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

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

um: init cpu_tasks[] earlier

This is currently done in uml_finishsetup(), but e.g. with
KCOV enabled we'll crash because some init code can call
into e.g. memparse(), which has coverage annotations, and
then the checks in check_kcov_mode() crash because current
is NULL.

Simply initialize the cpu_tasks[] array statically, which
fixes the crash. For the later SMP work, it seems to have
not really caused any problems yet, but initialize all of
the entries anyway.

The Linux kernel CVE team has assigned CVE-2025-71115 to this issue.


Affected and fixed versions
===========================

	Fixed in 6.18.3 with commit dbbf6d47130674640cd12a0781a0fb2a575d0e44
	Fixed in 6.19-rc1 with commit 7b5d4416964c07c902163822a30a622111172b01

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-71115
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	arch/um/kernel/process.c
	arch/um/kernel/um_arch.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/dbbf6d47130674640cd12a0781a0fb2a575d0e44
	https://git.kernel.org/stable/c/7b5d4416964c07c902163822a30a622111172b01