linux-cve-announce - CVE-2025-68186: ring-buffer: Do not warn in ring_buffer_map_get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025121633-CVE-2025-68186-8a42@gregkh>
Date: Tue, 16 Dec 2025 14:43:47 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68186: ring-buffer: Do not warn in ring_buffer_map_get_reader() when reader catches up

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

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

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

ring-buffer: Do not warn in ring_buffer_map_get_reader() when reader catches up

The function ring_buffer_map_get_reader() is a bit more strict than the
other get reader functions, and except for certain situations the
rb_get_reader_page() should not return NULL. If it does, it triggers a
warning.

This warning was triggering but after looking at why, it was because
another acceptable situation was happening and it wasn't checked for.

If the reader catches up to the writer and there's still data to be read
on the reader page, then the rb_get_reader_page() will return NULL as
there's no new page to get.

In this situation, the reader page should not be updated and no warning
should trigger.

The Linux kernel CVE team has assigned CVE-2025-68186 to this issue.


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

	Issue introduced in 6.10 with commit 117c39200d9d760cbd5944bb89efb7b9c51965aa and fixed in 6.12.58 with commit b42dbef4f208326271434d5ab71c4129a3ddd1a9
	Issue introduced in 6.10 with commit 117c39200d9d760cbd5944bb89efb7b9c51965aa and fixed in 6.17.8 with commit 6f5c4f8109fa4d0955b3712597a26b310bdc736f
	Issue introduced in 6.10 with commit 117c39200d9d760cbd5944bb89efb7b9c51965aa and fixed in 6.18 with commit aa997d2d2a0b2e76f4df0f1f12829f02acb4fb6b

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-2025-68186
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:
	kernel/trace/ring_buffer.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/b42dbef4f208326271434d5ab71c4129a3ddd1a9
	https://git.kernel.org/stable/c/6f5c4f8109fa4d0955b3712597a26b310bdc736f
	https://git.kernel.org/stable/c/aa997d2d2a0b2e76f4df0f1f12829f02acb4fb6b