Re: 4.9.208 regression in perf building

[Jin, Yao]

On 1/6/2020 6:25 AM, Jiri Olsa wrote:
> On Sun, Jan 05, 2020 at 12:06:07PM -0800, Akemi Yagi wrote:
> > On Sun, Jan 5, 2020 at 11:36 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> > > On Sun, Jan 05, 2020 at 10:21:25AM -0800, Akemi Yagi wrote:
> > > > Adding Arnaldo and Jiri to the CC list.
> > > >
> > > > On Sun, Jan 5, 2020 at 9:01 AM Gordan Bobic <gordan@xxxxxxxxxxxxx> wrote:
> > > > > It looks like 4.9.208 introduces a build regression for perf:
> > > > >
> > > > > make -f /builddir/build/BUILD/kernel-4.9.208/linux-4.9.208-1.el7.x86_64/tools/build/Makefile.build
> > > > > dir=. obj=perf
> > > >
> > > > >   -c -o builtin-report.o builtin-report.c
> > > > > builtin-report.c: In function âreport__setup_sample_typeâ:
> > > > > builtin-report.c:296:6: error: âdwarf_callchain_usersâ undeclared
> > > > > (first use in this function)
> > > > >    if (dwarf_callchain_users) {
> > > > >        ^
> > > > > builtin-report.c:296:6: note: each undeclared identifier is reported
> > > > > only once for each function it appears in
> > > > > mv: cannot stat â./.builtin-report.o.tmpâ: No such file or directory
> > > > > make[3]: *** [builtin-report.o] Error 1
> > > > > make[2]: *** [perf-in.o] Error 2
> > > > > make[1]: *** [sub-make] Error 2
> > > > > make: *** [all] Error 2
> > > > >
> > > > > 4,9.207 works fine.
> > > >
> > > > The regression was caused by the following patch:
> > > >
> > > > https://lore.kernel.org/lkml/20191021133834.25998-7-acme@xxxxxxxxxx/
> > > >
> > > > To fix this, 'dwarf_callchain_users' needs to be declared.
> > >
> > > hum, I see it's declared in callchain.h which is included in builtin-report.c
> > > also I can't see that same stuff like you have on line 296.. what sources are you on?
> > >
> > > could you please check with latest Arnaldo's perf/core?
> > >    git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git
> > >
> > > thanks,
> > > jirka
> >
> > This is kernel 4.4.208 that was released today.
> > 'dwarf_callchain_users' is not declared in this kernel. I'm afraid it
> > was missed when the aforementioned patch was backported.
>
> so 'dwarf_callchain_users' was introduced with:
>    eabad8c6856f perf unwind: Do not look just at the global callchain_param.record_mode
>
> which wasn't backported to 4.4.y and it seems it will need more
> dependencies to be applied properly
>
> however if I revert aforementioned patch:
>    faece3af8072 perf report: Add warning when libunwind not compiled in
>
> it compiles for me.. actualy I'm not sure why it went to stable,
> it's just user info/warning
>
> jirka

Yes, agree with Jiri, this patch is only warning for user, but not for 
fixing some issues.

Thanks
Jin Yao