Messages in this thread | | | Date | Wed, 27 Nov 2013 18:54:42 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH v2] use -fstack-protector-strong |
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* Kees Cook <keescook@chromium.org> wrote:
> On Wed, Nov 27, 2013 at 3:27 AM, Ingo Molnar <mingo@kernel.org> wrote: > > > > * Kees Cook <keescook@chromium.org> wrote: > > > >> On a defconfig x86_64 build (with CONFIG_CC_STACKPROTECTOR enabled), the > >> delta in size is just under 9% larger: > >> > >> -rwxrwxr-x 1 kees kees 22134340 Nov 26 10:28 vmlinux.gcc-4.8 > >> -rwxrwxr-x 1 kees kees 22123870 Nov 26 10:40 vmlinux.gcc-4.9 > >> -rwxrwxr-x 1 kees kees 24225118 Nov 26 10:42 vmlinux.gcc-4.9+strong > > > > Please run it through 'size' so that we know the real text size > > increases. > > text data bss dec hex filename > 11407474 1453792 1191936 14053202 d66f52 vmlinux.gcc-4.8 > 11458837 1457504 1191936 14108277 d74675 vmlinux.gcc-4.9 > 11682929 1457504 1191936 14332369 dab1d1 vmlinux.gcc-4.9+strong > > Looks to be 2% for defconfig. That's way better. Shall I send a v3?
Well, it's better than 9%, but still almost an order of magnitude higher than the cost is today, and a lot of distros have CONFIG_CC_STACKPROTECTOR=y.
So it would be nice to measure how much the instruction count goes up in some realistic system-bound test. How much does something like kernel/built-in.o increase, as per 'size' output?
Thanks,
Ingo
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