Subject: CVE-2022-48981: drm/shmem-helper: Remove errant put in error path

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

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

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

drm/shmem-helper: Remove errant put in error path

drm_gem_shmem_mmap() doesn't own this reference, resulting in the GEM
object getting prematurely freed leading to a later use-after-free.

The Linux kernel CVE team has assigned CVE-2022-48981 to this issue.

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

	Issue introduced in 5.2 with commit 2194a63a818d and fixed in 5.4.227 with commit 585a07b82005
	Issue introduced in 5.2 with commit 2194a63a818d and fixed in 5.10.159 with commit 6a4da05acd06
	Issue introduced in 5.2 with commit 2194a63a818d and fixed in 5.15.83 with commit 83e3da8bb92f
	Issue introduced in 5.2 with commit 2194a63a818d and fixed in 6.0.13 with commit 586847b98e20
	Issue introduced in 5.2 with commit 2194a63a818d and fixed in 6.1 with commit 24013314be6e

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-2022-48981
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/gpu/drm/drm_gem_shmem_helper.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/585a07b820059462e0c93b76c7de2cd946b26b40
	https://git.kernel.org/stable/c/6a4da05acd062ae7774b6b19cef2b7d922902d36
	https://git.kernel.org/stable/c/83e3da8bb92fcfa7a1d232cf55f9e6c49bb84942
	https://git.kernel.org/stable/c/586847b98e20ab02212ca5c1fc46680384e68a28
	https://git.kernel.org/stable/c/24013314be6ee4ee456114a671e9fa3461323de8