CVE-2023-53095: drm/ttm: Fix a NULL pointer dereference

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-02 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: drm/ttm: Fix a NULL pointer dereference The LRU mechanism may look up a resource in the process of being removed from an object. The locking rules here are a bit unclear but it looks currently like res->bo assignment is protected by the LRU lock, whereas bo->resource is protected by the object lock, while *clearing* of bo->resource is also protected by the LRU lock. This means that if we check that bo->resource points to the LRU resource under the LRU lock we should be safe. So perform that check before deciding to swap out a bo. That avoids dereferencing a NULL bo->resource in ttm_bo_swapout().

Affected products

Linux kernel: from 5.19 before 6.1.21; from 6.2 before 6.2.8; 6.3-rc1, 6.3-rc2 — fixed in 6.1.21, 6.2.8

How to fix

Upgrade to a fixed version: Linux kernel 6.1.21, 6.2.8. Check the vendor advisory for mitigations.

References

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