CVE-2026-98518: drm/nouveau/dmem: pin VRAM for the whole registered range

CVE-2026-98518: drm/nouveau/dmem: pin VRAM for the whole registered range

[Greg Kroah-Hartman]

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

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

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

drm/nouveau/dmem: pin VRAM for the whole registered range

Commit c32287471077 ("gpu/drm/nouveau: enable THP support for GPU memory
migration") grew the device-private region that
nouveau_dmem_chunk_alloc() registers from DMEM_CHUNK_SIZE to
DMEM_CHUNK_SIZE * NR_CHUNKS, but left the VRAM buffer object backing that
region at DMEM_CHUNK_SIZE.

nouveau_dmem_page_addr() returns chunk->bo->offset plus the page's offset
within the registered region, so every page past the first chunk resolves
to VRAM outside the buffer object.

Size the buffer object to the region it backs.

The Linux kernel CVE team has assigned CVE-2026-98518 to this issue.


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

	Issue introduced in 6.19 with commit c3228747107705d47c7e9a03598a434a0380cb73 and fixed in 7.2.9 with commit 06c69c64686a31783c8bec6495dc22822d38c4ce
	Issue introduced in 6.19 with commit c3228747107705d47c7e9a03598a434a0380cb73 and fixed in 7.3-rc5 with commit 64ca4cdd1031206424e6455f0ae4fb0560d8f46a

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-2026-98518
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/nouveau/nouveau_dmem.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/06c69c64686a31783c8bec6495dc22822d38c4ce
	https://git.kernel.org/stable/c/64ca4cdd1031206424e6455f0ae4fb0560d8f46a