Re: [PATCH] [RFC] Revert "bpf: Fix ORC unwinding in non-JIT BPF code"

[Josh Poimboeuf]

On Mon, Jul 08, 2019 at 02:45:23PM +0200, Arnd Bergmann wrote:
> Apparently this was a bit premature, at least I still get this
> warning with gcc-8.1:
> 
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x44d2: sibling call from callable instruction with modified stack frame
> 
> This reverts commit b22cf36c189f31883ad0238a69ccf82aa1f3b16b.
> 
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Yes, I have been working on a fix.

The impact is that ORC unwinding is broken in this function for
CONFIG_RETPOLINE=n.

I don't think we want to revert this patch though, because that will
broaden the impact to the CONFIG_RETPOLINE=y case.  Anyway I hope to
have fixes soon.

-- 
Josh