On Tue, 29 Sep 2020 at 01:20, Kees Cook <keescook@chromium.org> wrote:
Note that I still can't explain what you're seeing. /proc/kallsyms shouldn't be affected by these patches -- I would expect it to either report the true value or 00s.
I will disable kptr_restrict and check or, I will enable CONFIG_DEBUG_CONSOLE_UNHASHED_POINTERS and check.
I would start with kptr_restrict=0 and see if that changes the contents of /proc/kallsyms. If it does, then it is the hashing. If it doesn't, well, we're back to square one. :)
Actually in that board, the kptr_restrict=0 already in both case: 4.9 and 4.14 Kernel boards. In another board with 4.14 and kptr_restrict=2, I see that the addresses are 00 always. I further checked that when I enable this config: CONFIG_DEBUG_CONSOLE_UNHASHED_POINTERS, then the addresses are remaining the same in every boot. But this particular config is not present in 4.9 Kernel. So, I think it is controlled using this config. -- Pintu