Re: [PATCHv2] lkdtm: Add READ_AFTER_FREE test

From: Kees Cook
Date: Tue Feb 23 2016 - 17:38:11 EST


On Tue, Feb 23, 2016 at 1:25 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:

> zero poison only:
> DEBUG_PAGEALLOC=n
> PAGE_POISONING=y
> PAGE_POISONING_NO_SANITY=y
> PAGE_POISONING_ZERO=y
> page_poison=on

This combo (in next-20160223) results in an unusable system. :(

[ 1.754183] random: init urandom read with 11 bits of entropy available
[ 1.768449] hostname (1171) used greatest stack depth: 11808 bytes left
[ 1.787954] BUG: Bad page map in process init pte:3d656c6f736e6f63
pmd:00020067
[ 1.789177] addr:00007f9f68200000 vm_flags:00000070 anon_vma:
(null) mapping:ffff88007c314058 index:141
[ 1.790564] file:libdl-2.19.so fault:ext4_filemap_fault
mmap:ext4_file_mmap readpage:ext4_readpage

-Kees

--
Kees Cook
Chrome OS & Brillo Security