CVE-2026-72244: gpu/buddy: bail out of try_harder when alignment cannot be honoured

CVE-2026-72244: gpu/buddy: bail out of try_harder when alignment cannot be honoured

[Greg Kroah-Hartman]

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

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

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

gpu/buddy: bail out of try_harder when alignment cannot be honoured

The try_harder contiguous fallback could return a range whose start
offset did not match the caller's min_block_size. When a candidate's
start is misaligned, realign it: free the misaligned run and reallocate
exactly @size at the next lower min_block_size boundary. This keeps the
returned size unchanged with no surplus to trim, and rejects the request
only when no aligned candidate fits.

v2: align misaligned candidates down to min_block_size instead of
    bailing out, for both the RHS and LHS paths (Matthew).

The Linux kernel CVE team has assigned CVE-2026-72244 to this issue.


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

	Issue introduced in 6.7 with commit 0a1844bf0b532d84324453374ad6845f64066c28 and fixed in 6.12.101 with commit 4289531106ee175a6eb45db7d4f2734d1dae9887
	Issue introduced in 6.7 with commit 0a1844bf0b532d84324453374ad6845f64066c28 and fixed in 6.18.42 with commit 7185c5262435b93e5eeffa647008992256b9c51a
	Issue introduced in 6.7 with commit 0a1844bf0b532d84324453374ad6845f64066c28 and fixed in 7.1.5 with commit 419d7d9306491f3e0e417cf794844c73cabee090
	Issue introduced in 6.7 with commit 0a1844bf0b532d84324453374ad6845f64066c28 and fixed in 7.2-rc3 with commit 56bc6384314fb9ae98975fb2af8b143097ede3dc

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-2026-72244
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/buddy.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/4289531106ee175a6eb45db7d4f2734d1dae9887
	https://git.kernel.org/stable/c/7185c5262435b93e5eeffa647008992256b9c51a
	https://git.kernel.org/stable/c/419d7d9306491f3e0e417cf794844c73cabee090
	https://git.kernel.org/stable/c/56bc6384314fb9ae98975fb2af8b143097ede3dc