Subject: CVE-2022-48893: drm/i915/gt: Cleanup partial engine discovery failures

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

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

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

drm/i915/gt: Cleanup partial engine discovery failures

If we abort driver initialisation in the middle of gt/engine discovery,
some engines will be fully setup and some not. Those incompletely setup
engines only have 'engine->release == NULL' and so will leak any of the
common objects allocated.

v2:
 - Drop the destroy_pinned_context() helper for now.  It's not really
   worth it with just a single callsite at the moment.  (Janusz)

The Linux kernel CVE team has assigned CVE-2022-48893 to this issue.

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

	Fixed in 6.1.7 with commit 5c855bcc7306
	Fixed in 6.2 with commit 78a033433a5a

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-2022-48893
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/i915/gt/intel_engine_cs.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/5c855bcc730656c4b7d30aaddcd0eafc7003e112
	https://git.kernel.org/stable/c/78a033433a5ae4fee85511ee075bc9a48312c79e