CVE-2026-90409: drm/panthor: Add vm_bind region with kbo range overlap check

CVE-2026-90409: drm/panthor: Add vm_bind region with kbo range overlap check

[Greg Kroah-Hartman]

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

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

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

drm/panthor: Add vm_bind region with kbo range overlap check

When a VM is created, caller has to specify the range of the address space
carve-out set aside for mapping kernel BO's. That means vm_bind mappings of
UM-exposed BO's should not intersect with that region, but at the moment
we're not checking this.

At first, I thought of giving these values to drm_gpuvm_init() through its
reserve_{offset, range} arguments, but it turns out that is meant for VM
address spans that are not managed through the usual drm_gpuvm split/merge
circuit, so storing the end of the user VA range at VM creation time and
doing a quick check in the vm_bind ioctl path was the simplest workaround.

The new check also makes sure vm_bind range doesn't overflow the size of a
64-bit unsigned integer. That was already being done further down the call
stack inside drm_gpuvm_sm_map -> drm_gpuvm_range_valid, but it's best to
fail early in the driver before GPUVM functions are invoked so that we
won't waste time allocating vm_bind context resources.

The Linux kernel CVE team has assigned CVE-2026-90409 to this issue.


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

	Issue introduced in 6.10 with commit 647810ec247641eb5aec8caef818919a4518a0b1 and fixed in 7.2.6 with commit 761cf9c63274a5b711c3dc829601723215710d2d
	Issue introduced in 6.10 with commit 647810ec247641eb5aec8caef818919a4518a0b1 and fixed in 7.3-rc1 with commit 985f5e12f3cdf43030e13c2bbd154913133b5c3f

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-2026-90409
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/panthor/panthor_mmu.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/761cf9c63274a5b711c3dc829601723215710d2d
	https://git.kernel.org/stable/c/985f5e12f3cdf43030e13c2bbd154913133b5c3f