CVE-2026-64050: drm/msm/dpu: don't mix devm and drmm functions

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

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

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

drm/msm/dpu: don't mix devm and drmm functions

Mixing devm and drmm functions will result in a use-after-free on msm
driver teardown if userspace keeps a reference on the drm device:
The WB connector data will be destroyed because of the use of
devm_kzalloc()), while the usersoace still can try interacting with the
WB connector (which uses drmm_ functions).

Change dpu_writeback_init() to use drmm_.

Patchwork: https://patchwork.freedesktop.org/patch/722656/

The Linux kernel CVE team has assigned CVE-2026-64050 to this issue.


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

	Issue introduced in 6.18 with commit 0b37ac63fc9db7779168ad18d7e6e8ab9df6a40b and fixed in 6.18.34 with commit ff58e5ef1b46ce614af048d2d04986df05ffab90
	Issue introduced in 6.18 with commit 0b37ac63fc9db7779168ad18d7e6e8ab9df6a40b and fixed in 7.0.11 with commit 95048a12f48c627bc2ccc4d84f87640630ba2bdb
	Issue introduced in 6.18 with commit 0b37ac63fc9db7779168ad18d7e6e8ab9df6a40b and fixed in 7.1 with commit c0c70a11365cba7fba25a77463582bcec0f7846e

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-2026-64050
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/msm/disp/dpu1/dpu_writeback.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/ff58e5ef1b46ce614af048d2d04986df05ffab90
	https://git.kernel.org/stable/c/95048a12f48c627bc2ccc4d84f87640630ba2bdb
	https://git.kernel.org/stable/c/c0c70a11365cba7fba25a77463582bcec0f7846e