CVE-2025-68181

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

drm/radeon: Remove calls to drm_put_dev()

Since the allocation of the drivers main structure was changed to devm_drm_dev_alloc() drm_put_dev()'ing to trigger it to be free'd should be done by devres.

However, drm_put_dev() is still in the probe error and device remove paths. When the driver fails to probe warnings like the following are shown because devres is trying to drm_put_dev() after the driver already did it.

[ 5.642230] radeon 0000:01:05.0: probe with driver radeon failed with error -22 [ 5.649605] ------------[ cut here ]------------ [ 5.649607] refcount_t: underflow; use-after-free. [ 5.649620] WARNING: CPU: 0 PID: 357 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110

(cherry picked from commit 3eb8c0b4c091da0a623ade0d3ee7aa4a93df1ea4)

A low-impact use-after-free flaw was found in the Linux kernel radeon DRM driver, affecting Red Hat Enterprise Linux 9 and 10. After the driver's main structure allocation was changed to devm_drm_dev_alloc(), calls to drm_put_dev() remained in the probe error and device removal paths, so the kernel's device resource management code (devres) attempts to release the structure after the driver has already released it. This triggers a reference count underflow (use-after-free) warning when the radeon driver fails to probe or when a device is removed. Triggering the issue requires local access on a system with radeon (AMD GPU) hardware and specific conditions in the driver's error and removal paths, and the impact is limited to availability (Red Hat CVSS 4.7, Moderate). Red Hat rates this issue lower than the upstream CVE.org severity of Important (7.8), which assumes confidentiality and integrity impacts that the technical evidence does not support. Red Hat Enterprise Linux 7 and 8 and Red Hat In-Vehicle OS 1.1 are not affected because the vulnerable code is not present in those releases, and Red Hat Enterprise Linux 6 Extended Lifecycle Support is out of support scope. Because the flaw is confined to the radeon driver's probe-failure and device-removal paths and has low security impact, the fix is deferred for the affected RHEL 9 and RHEL 10 releases; the residual risk is a kernel warning and a potential use-after-free limited to those code paths on systems using the radeon driver.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.