Re: [PATCH] x86: Allow for exclusions in checking RETHUNK

[Josh Poimboeuf]

On Thu, Jul 14, 2022 at 09:18:12AM +0200, Peter Zijlstra wrote:
> On Wed, Jul 13, 2022 at 04:55:56PM -0700, Josh Poimboeuf wrote:
> > Here's the ANNOTATE_UNSAFE_RET idea.
> 
> Right, I suppose that strictly speaking the compiler can do whatever and
> there's no actual guarantee the annotation hits the RET instruction, in
> practise it should work, esp. since noinstr.

Hm, KASAN is introducing a weird function, resulting in a naked return
warning since we have RETHUNK_CFLAGS removed on that file.

0000000000000000 <_sub_I_00099_0>:
   0:	e8 00 00 00 00       	call   5 <_sub_I_00099_0+0x5>	1: R_X86_64_PLT32	__tsan_init-0x4
   5:	c3                   	ret    


Looks like the "KASAN_SANITIZE_rodata.o := n" isn't working somehow?

-- 
Josh