Re: Getting empty callchain from perf_callchain_kernel()

[Peter Zijlstra]

On Fri, May 17, 2019 at 04:15:39PM +0800, Kairui Song wrote:
> Hi, I think the actual problem is that bpf_get_stackid_tp (and maybe
> some other bfp functions) is now broken, or, strating an unwind
> directly inside a bpf program will end up strangely. It have following
> kernel message:

Urgh, what is that bpf_get_stackid_tp() doing to get the regs? I can't
follow.