Re: kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without frame pointer save/setup

From: Josh Poimboeuf
Date: Mon Aug 26 2019 - 11:18:17 EST


On Mon, Aug 26, 2019 at 10:42:53PM +0800, He Zhe wrote:
> Hi All,
>
> Since 3193c0836f20 ("bpf: Disable GCC -fgcse optimization for ___bpf_prog_run()"),
> We have got the following warning,
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without frame pointer save/setup
>
> If reverting the above commit, we will get the following warning,
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x8b9: sibling call from callable instruction with modified stack frame
> if CONFIG_RETPOLINE=n, and no warning if CONFIG_RETPOLINE=y

Can you please share the following:

- core.o file

The following would also be helpful for me to try to recreate it:

- config file
- compiler version
- kernel version

--
Josh