Re: [PATCH v2 1/5] perf/x86: Always store regs->ip in perf_callchain_kernel()

[Josh Poimboeuf]

On Fri, Jun 14, 2019 at 01:56:15PM -0700, Alexei Starovoitov wrote:
> On Fri, Jun 14, 2019 at 12:56:40PM -0500, Josh Poimboeuf wrote:
> > From: Song Liu <songliubraving@xxxxxx>
> > 
> > The stacktrace_map_raw_tp BPF selftest is failing because the RIP saved
> > by perf_arch_fetch_caller_regs() isn't getting saved by
> > perf_callchain_kernel().
> > 
> > This was broken by the following commit:
> > 
> >   d15d356887e7 ("perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER")
> > 
> > With that change, when starting with non-HW regs, the unwinder starts
> > with the current stack frame and unwinds until it passes up the frame
> > which called perf_arch_fetch_caller_regs().  So regs->ip needs to be
> > saved deliberately.
> > 
> > Fixes: d15d356887e7 ("perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER")
> > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> > Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> 
> It's not cool to remove people's SOB.
> It's Song's patch. His should be first and your second.

His original patch didn't have an SOB.  I preserved the "From" field.

-- 
Josh