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

efi: fix potential NULL deref in efi_mem_reserve_persistent

When iterating on a linked list, a result of memremap is dereferenced
without checking it for NULL.

This patch adds a check that falls back on allocating a new page in
case memremap doesn't succeed.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

[ardb: return -ENOMEM instead of breaking out of the loop]