Subject: CVE-2020-36784: i2c: cadence: fix reference leak when pm_runtime_get_sync fails

From: Greg Kroah-Hartman <[email-masked]>

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

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

i2c: cadence: fix reference leak when pm_runtime_get_sync fails

The PM reference count is not expected to be incremented on
return in functions cdns_i2c_master_xfer and cdns_reg_slave.

However, pm_runtime_get_sync will increment pm usage counter
even failed. Forgetting to putting operation will result in a
reference leak here.

Replace it with pm_runtime_resume_and_get to keep usage
counter balanced.

The Linux kernel CVE team has assigned CVE-2020-36784 to this issue.

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

	Issue introduced in 4.5 with commit 7fa32329ca03 and fixed in 5.10.37 with commit 30410519328c
	Issue introduced in 4.5 with commit 7fa32329ca03 and fixed in 5.11.21 with commit d57ff04e0ed6
	Issue introduced in 4.5 with commit 7fa32329ca03 and fixed in 5.12.4 with commit a45fc41beed8
	Issue introduced in 4.5 with commit 7fa32329ca03 and fixed in 5.13 with commit 23ceb8462dc6

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-2020-36784
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/i2c/busses/i2c-cadence.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/30410519328c94367e561fd878e5f0d3a0303585
	https://git.kernel.org/stable/c/d57ff04e0ed6f3be1682ae861ead33f879225e07
	https://git.kernel.org/stable/c/a45fc41beed8e0fe31864619c34aa00797fb60c1
	https://git.kernel.org/stable/c/23ceb8462dc6f4b4decdb5536a7e5fc477cdf0b6