CVE-2024-58091: drm/fbdev-dma: Add shadow buffering for deferred I/O

Vulnerability summary

CVE-2024-58091 is a high (CVSS 7.8) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 11.8% of scored vulnerabilities.

Timeline

1. 27-03-2025
   PublishedVulnerability first disclosed.
2. 05-08-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: drm/fbdev-dma: Add shadow buffering for deferred I/O DMA areas are not necessarily backed by struct page, so we cannot rely on it for deferred I/O. Allocate a shadow buffer for drivers that require deferred I/O and use it as framebuffer memory. Fixes driver errors about being "Unable to handle kernel NULL pointer dereference at virtual address" or "Unable to handle kernel paging request at virtual address". The patch splits drm_fbdev_dma_driver_fbdev_probe() in an initial allocation, which creates the DMA-backed buffer object, and a tail that sets up the fbdev data structures. There is a tail function for direct memory mappings and a tail function for deferred I/O with the shadow buffer. It is no longer possible to use deferred I/O without shadow buffer. It can be re-added if there exists a reliably test for usable struct page in the allocated DMA-backed buffer object.

• CWE-476NULL Pointer DereferenceThe product dereferences a pointer that it expects to be valid but is NULL.