CVE-2026-31744

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

PM: EM: Fix NULL pointer dereference when perf domain ID is not found

devenergymodelnlgetperfdomainsdoit() calls emperfdomaingetby_id() but does not check the return value before passing it to __emnlgetpdsize(). When a caller supplies a non-existent perf domain ID, emperfdomaingetby_id() returns NULL, and __emnlgetpdsize() immediately dereferences pd->cpus (struct offset 0x30), causing a NULL pointer dereference.

The sister handler devenergymodelnlgetperftabledoit() already handles this correctly via _emnlgetpdtableid(), which returns NULL and causes the caller to return -EINVAL. Add the same NULL check in the get-perf-domains do handler.

[ rjw: Subject and changelog edits ]