CVE-2024-46851: drm/amd/display: Avoid race between dcn10_set_drr() and dc_state_destruct()

Vulnerability summary

CVE-2024-46851 is a medium (CVSS 4.7) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6.4% of scored vulnerabilities.

Timeline

1. 27-09-2024
   PublishedVulnerability first disclosed.
2. 11-05-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Avoid race between dcn10_set_drr() and dc_state_destruct() dc_state_destruct() nulls the resource context of the DC state. The pipe context passed to dcn10_set_drr() is a member of this resource context. If dc_state_destruct() is called parallel to the IRQ processing (which calls dcn10_set_drr() at some point), we can end up using already nulled function callback fields of struct stream_resource. The logic in dcn10_set_drr() already tries to avoid this, by checking tg against NULL. But if the nulling happens exactly after the NULL check and before the next access, then we get a race. Avoid this by copying tg first to a local variable, and then use this variable for all the operations. This should work, as long as nobody frees the resource pool where the timing generators live. (cherry picked from commit a3cc326a43bdc48fbdf53443e1027a03e309b643)

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