pstore/zone: Add a null pointer check to the psz_kmsg_read

These records connect through source-stated identifiers. Shared identifiers or dates alone do not establish shared exposure, root cause or applicability.

CVE-2024-35940 · Microsoft / collected KEV context

cve-program · CVE-2024-35940

• https://git.kernel.org/stable/c/98e2b97acb875d65bdfc75fc408e67975cef3041
• https://git.kernel.org/stable/c/0ff96ec22a84d80a18d7ae8ca7eb111c34ee33bb
• https://git.kernel.org/stable/c/635594cca59f9d7a8e96187600c34facb8bc0682
• https://git.kernel.org/stable/c/ec7256887d072f98c42cdbef4dcc80ddf84c7a70
• https://git.kernel.org/stable/c/6f9f2e498eae7897ba5d3e33908917f68ff4abcc
• https://git.kernel.org/stable/c/98bc7e26e14fbb26a6abf97603d59532475e97f8

No related operational record is retained in the current change model.