CVE-2025-39705

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

drm/amd/display: fix a Null pointer dereference vulnerability

[Why]
A null pointer dereference vulnerability exists in the AMD display driver's
(DC module) cleanup function dc_destruct().
When display control context (dc->ctx) construction fails
(due to memory allocation failure), this pointer remains NULL.
During subsequent error handling when dc_destruct() is called,
there's no NULL check before dereferencing the perf_trace member
(dc->ctx->perf_trace), causing a kernel null pointer dereference crash.

[How]
Check if dc->ctx is non-NULL before dereferencing.

(Updated commit text and removed unnecessary error message)
(cherry picked from commit 9dd8e2ba268c636c240a918e0a31e6feaee19404)