CVE-2026-52950: drm/xe/dma-buf: fix UAF with retry loop

CVE-2026-52950: drm/xe/dma-buf: fix UAF with retry loop

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

drm/xe/dma-buf: fix UAF with retry loop

Retry doesn't work here, since bo will be freed on error, leading to
UAF. However, now that we do the alloc & init before the attach, we can
now combine this as one unit and have the init do the alloc for us. This
should make the retry safe.

Reported by Sashiko.

v2: Fix up the error unwind (CI)

(cherry picked from commit 479669418253e0f27f8cf5db01a731352ea592e7)

The Linux kernel CVE team has assigned CVE-2026-52950 to this issue.


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

	Issue introduced in 6.18 with commit eb289a5f6cc668853f9b2ea6aca04afe58ed11c7 and fixed in 6.18.33 with commit 39fdac6be02eb7c3460518c1c4085f75f935c4ce
	Issue introduced in 6.18 with commit eb289a5f6cc668853f9b2ea6aca04afe58ed11c7 and fixed in 7.0.10 with commit 827062952ed9bdf4220466c1f05ce452d04bdedf
	Issue introduced in 6.18 with commit eb289a5f6cc668853f9b2ea6aca04afe58ed11c7 and fixed in 7.1 with commit 155a372a1cc50fa93387c5d3cdfd614a61e1afd1

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-2026-52950
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/xe/xe_dma_buf.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/39fdac6be02eb7c3460518c1c4085f75f935c4ce
	https://git.kernel.org/stable/c/827062952ed9bdf4220466c1f05ce452d04bdedf
	https://git.kernel.org/stable/c/155a372a1cc50fa93387c5d3cdfd614a61e1afd1