Now EFI region is mistakenly counted into KASLR VA space for randomization because of misusing EFI_VA_START macro and assuming EFI_VA_START < EFI_VA_END. In fact EFI region reserved for runtime services virtual mapping will be allocated using a top-down schema. It will be reused by kexec/kdump kernel.
So the mistake will cause failure because vmemmap may be randomized to own EFI region and stomped on the EFI virtual mapping. It's need be fixed. The original post can be found in below link. And this repost just updated patch log, no new code change. The patch 1/2 need be added to stabe kernel after 4.8+. https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1347835.html Baoquan He (2): x86/mm/KASLR: EFI region is mistakenly included into KASLR VA space for randomization x86/efi: Clean up a minor mistake in code comment arch/x86/mm/kaslr.c | 4 ++-- arch/x86/platform/efi/efi_64.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) -- 2.5.5
