CVE-2026-68244: drm/i915/gem: Do not leak siblings[] on proto context error

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

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

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

drm/i915/gem: Do not leak siblings[] on proto context error

After a successful BALANCE/PARALLEL_SUBMIT extension on context
creation, error during processing of next user extension leaks
the siblings[] array. Fix that.

Discovered using AI-assisted static analysis confirmed by
Intel Product Security.

(cherry picked from commit aa65e0a4b51b3b54b53e4142aaa2d997aa1061ff)

The Linux kernel CVE team has assigned CVE-2026-68244 to this issue.


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

	Issue introduced in 5.15 with commit d4433c7600f794623d6802395542cf4ca4f1b1f9 and fixed in 6.6.148 with commit f014702fbd48d06a3d7a06e4bb4075d406376cf0
	Issue introduced in 5.15 with commit d4433c7600f794623d6802395542cf4ca4f1b1f9 and fixed in 6.12.101 with commit 8431a4d7ff95c7f9c6fb1dbbbc9cdadf29d4f6d5
	Issue introduced in 5.15 with commit d4433c7600f794623d6802395542cf4ca4f1b1f9 and fixed in 6.18.42 with commit 37951ce1567ccf8c86c7a1b8fb7d55a32c821b87
	Issue introduced in 5.15 with commit d4433c7600f794623d6802395542cf4ca4f1b1f9 and fixed in 7.1.6 with commit 6cdbef8f60f313684e641628d64aa85960080d3f
	Issue introduced in 5.15 with commit d4433c7600f794623d6802395542cf4ca4f1b1f9 and fixed in 7.2-rc3 with commit eed3de2acf6aa5154d49098b026710b646db67ee

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-2026-68244
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/gem/i915_gem_context.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/f014702fbd48d06a3d7a06e4bb4075d406376cf0
	https://git.kernel.org/stable/c/8431a4d7ff95c7f9c6fb1dbbbc9cdadf29d4f6d5
	https://git.kernel.org/stable/c/37951ce1567ccf8c86c7a1b8fb7d55a32c821b87
	https://git.kernel.org/stable/c/6cdbef8f60f313684e641628d64aa85960080d3f
	https://git.kernel.org/stable/c/eed3de2acf6aa5154d49098b026710b646db67ee