CVE-2026-98521

/// Technical description

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

drm/i915: fix incorrect RCU teardown order

i915_gem_busy_ioctl uses dma_resv_for_each_fence_unlocked() to iterate

over the fences in an GEM object without holding a reference but only

the RCU read side lock.

What can happen here is that the GEM object is destroyed concurrently

while i915_gem_busy_ioctl is still running. This won't free the GEM

objects memory, but still drops all the dma_fence references.

Now when dma_resv_for_each_fence_unlocked() sees a destroyed dma_fence it

assumes that a new fence list was installed and re-starts the loop.

But in the case of a destroyed GEM object a new fence list is never

installed, only the old one freed and therefore the iteration never

finishes resulting in an endless loop.

The solution is to drop the fence references only after the RCU grace

period.

The fixes tag is not necessary the patch introducing the problem, but the

one making it so worse that we need to address i

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References