CVE-2021-47067: soc/tegra: regulators: Fix locking up when voltage-spread is out of range

CVE-2021-47067: soc/tegra: regulators: Fix locking up when voltage-spread is out of range

[Greg Kroah-Hartman]

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

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

soc/tegra: regulators: Fix locking up when voltage-spread is out of range

Fix voltage coupler lockup which happens when voltage-spread is out
of range due to a bug in the code. The max-spread requirement shall be
accounted when CPU regulator doesn't have consumers. This problem is
observed on Tegra30 Ouya game console once system-wide DVFS is enabled
in a device-tree.

The Linux kernel CVE team has assigned CVE-2021-47067 to this issue.


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

	Issue introduced in 5.5 with commit 783807436f36 and fixed in 5.10.37 with commit a1ad124c8368
	Issue introduced in 5.5 with commit 783807436f36 and fixed in 5.11.21 with commit dc4452867200
	Issue introduced in 5.5 with commit 783807436f36 and fixed in 5.12.4 with commit ff39adf5d31c
	Issue introduced in 5.5 with commit 783807436f36 and fixed in 5.13 with commit ef85bb582c41

Please see https://www.kernel.org or 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-2021-47067
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/soc/tegra/regulators-tegra30.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/a1ad124c836816fac8bd5e461d36eaf33cee4e24
	https://git.kernel.org/stable/c/dc4452867200fa94589b382740952b58aa1c3e6c
	https://git.kernel.org/stable/c/ff39adf5d31c72025bba799aec69c5c86d81d549
	https://git.kernel.org/stable/c/ef85bb582c41524e9e68dfdbde48e519dac4ab3d