CVE-2026-74420: drm/gpusvm: Reject VMAs with VM_IO or VM_PFNMAP when creating SVM ranges

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

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

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

drm/gpusvm: Reject VMAs with VM_IO or VM_PFNMAP when creating SVM ranges

VMAs marked with VM_IO or VM_PFNMAP are not backed by struct page
objects, which GPUSVM requires in order to operate correctly. In
particular, get_pages() relies on hmm_range_fault() to resolve struct
pages for the target range.

Attempting to create an SVM range on such VMAs results in repeated
get_pages() failures and can lead to an infinite loop inside a driver’s
page‑fault handler. Prevent this by rejecting ranges on VM_IO or
VM_PFNMAP VMAs and returning -EIO.

The Linux kernel CVE team has assigned CVE-2026-74420 to this issue.


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

	Issue introduced in 6.15 with commit 99624bdff8670795b678eafa6509aaad3a5c0175 and fixed in 6.18.40 with commit 353f26c74660bcbd8d82cd76622748e14a5a5db3
	Issue introduced in 6.15 with commit 99624bdff8670795b678eafa6509aaad3a5c0175 and fixed in 7.1.5 with commit 63f443384979563f16f70420f4fa85bba31238ca
	Issue introduced in 6.15 with commit 99624bdff8670795b678eafa6509aaad3a5c0175 and fixed in 7.2-rc1 with commit b82a225e57a334335a21462b75ee2223bc6efe6d

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-2026-74420
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/drm_gpusvm.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/353f26c74660bcbd8d82cd76622748e14a5a5db3
	https://git.kernel.org/stable/c/63f443384979563f16f70420f4fa85bba31238ca
	https://git.kernel.org/stable/c/b82a225e57a334335a21462b75ee2223bc6efe6d