CVE-2026-93052: misc: bcm-vk: Use acquire/release for msgq_inited

CVE-2026-93052: misc: bcm-vk: Use acquire/release for msgq_inited

[Greg Kroah-Hartman]

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

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

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

misc: bcm-vk: Use acquire/release for msgq_inited

bcm_vk_sync_msgq() fills the message queue information and then sets
msgq_inited. Readers call bcm_vk_drv_access_ok() before accessing the
message queues and their cached queue information.

atomic_set()/atomic_read() do not order those accesses. A reader can see
msgq_inited set while still seeing stale queue information. Use release
when publishing the initialized queues and acquire when checking the gate.

Keep the clear in bcm_vk_blk_drv_access() as atomic_set(). It closes the
gate and does not publish queue state to readers.

The Linux kernel CVE team has assigned CVE-2026-93052 to this issue.


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

	Issue introduced in 5.12 with commit 111d746bb4767ad476f80fe49067e3df3d9a9375 and fixed in 5.15.221 with commit bab66a9e30e39a06f3463b19f8c704386dfd5268
	Issue introduced in 5.12 with commit 111d746bb4767ad476f80fe49067e3df3d9a9375 and fixed in 6.1.188 with commit 679cfada6868723ccf162ec3b78c7402ff2405bf
	Issue introduced in 5.12 with commit 111d746bb4767ad476f80fe49067e3df3d9a9375 and fixed in 6.6.157 with commit f7a8f4cbc8cede0be55220367dc52b126e2d39e5
	Issue introduced in 5.12 with commit 111d746bb4767ad476f80fe49067e3df3d9a9375 and fixed in 6.12.110 with commit 1df3926ed8771edf286ff753428b243f334e6041
	Issue introduced in 5.12 with commit 111d746bb4767ad476f80fe49067e3df3d9a9375 and fixed in 6.18.52 with commit a45d6dd3c11e921882a2e74c7c8710b975f2eaa7
	Issue introduced in 5.12 with commit 111d746bb4767ad476f80fe49067e3df3d9a9375 and fixed in 7.2.6 with commit 4984277bc43f84d7506346a09b29af138246d54a
	Issue introduced in 5.12 with commit 111d746bb4767ad476f80fe49067e3df3d9a9375 and fixed in 7.3-rc1 with commit 61b101c6a150057b6d512421ed108aed16e822ea

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-2026-93052
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:
	drivers/misc/bcm-vk/bcm_vk_msg.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/bab66a9e30e39a06f3463b19f8c704386dfd5268
	https://git.kernel.org/stable/c/679cfada6868723ccf162ec3b78c7402ff2405bf
	https://git.kernel.org/stable/c/f7a8f4cbc8cede0be55220367dc52b126e2d39e5
	https://git.kernel.org/stable/c/1df3926ed8771edf286ff753428b243f334e6041
	https://git.kernel.org/stable/c/a45d6dd3c11e921882a2e74c7c8710b975f2eaa7
	https://git.kernel.org/stable/c/4984277bc43f84d7506346a09b29af138246d54a
	https://git.kernel.org/stable/c/61b101c6a150057b6d512421ed108aed16e822ea