CVE-2026-74416: drm/radeon: fix memory leak in radeon_ring_restore() on lock failure

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

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

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

drm/radeon: fix memory leak in radeon_ring_restore() on lock failure

radeon_ring_restore() takes ownership of the data buffer allocated by
radeon_ring_backup(). The caller (radeon_gpu_reset()) only frees it in
the non-restore branch; in the restore branch it relies on
radeon_ring_restore() to free it.

If radeon_ring_lock() fails, the function returned early without calling
kvfree(data), leaking the ring backup buffer on every GPU reset that
fails at the lock stage. During repeated GPU resets this causes
cumulative kernel memory exhaustion.

Free data before returning the error.

The Linux kernel CVE team has assigned CVE-2026-74416 to this issue.


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

	Issue introduced in 3.6 with commit 55d7c22192becd0ec827a6901899ff56fa985658 and fixed in 5.10.261 with commit 63912418f1fbb6456ea04bbcdf8f4d5090d23350
	Issue introduced in 3.6 with commit 55d7c22192becd0ec827a6901899ff56fa985658 and fixed in 5.15.212 with commit 919e3e398bf301c6418dffdcd5e5c4fd9be39cf7
	Issue introduced in 3.6 with commit 55d7c22192becd0ec827a6901899ff56fa985658 and fixed in 6.1.178 with commit 07c213f3499dd72e2922c1c73fe9ffea24874bef
	Issue introduced in 3.6 with commit 55d7c22192becd0ec827a6901899ff56fa985658 and fixed in 6.6.145 with commit 1c9ba32308c02c198c378fcdf06be9ffc3111147
	Issue introduced in 3.6 with commit 55d7c22192becd0ec827a6901899ff56fa985658 and fixed in 6.12.97 with commit eecfb76129ebef7e3aa41e18a4668cd91dfc6267
	Issue introduced in 3.6 with commit 55d7c22192becd0ec827a6901899ff56fa985658 and fixed in 6.18.40 with commit 06dc892561f5a08b2493c34c8ec2cb94dea33159
	Issue introduced in 3.6 with commit 55d7c22192becd0ec827a6901899ff56fa985658 and fixed in 7.1.5 with commit ccc42187fc2d0720947a63ce1b9e399d2c068ff4
	Issue introduced in 3.6 with commit 55d7c22192becd0ec827a6901899ff56fa985658 and fixed in 7.2-rc1 with commit 82f1d6042611d45b8b9de423bbcb4e0ced9ec62b

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-2026-74416
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/radeon/radeon_ring.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/63912418f1fbb6456ea04bbcdf8f4d5090d23350
	https://git.kernel.org/stable/c/919e3e398bf301c6418dffdcd5e5c4fd9be39cf7
	https://git.kernel.org/stable/c/07c213f3499dd72e2922c1c73fe9ffea24874bef
	https://git.kernel.org/stable/c/1c9ba32308c02c198c378fcdf06be9ffc3111147
	https://git.kernel.org/stable/c/eecfb76129ebef7e3aa41e18a4668cd91dfc6267
	https://git.kernel.org/stable/c/06dc892561f5a08b2493c34c8ec2cb94dea33159
	https://git.kernel.org/stable/c/ccc42187fc2d0720947a63ce1b9e399d2c068ff4
	https://git.kernel.org/stable/c/82f1d6042611d45b8b9de423bbcb4e0ced9ec62b