Re: [solved] Re: linux-next: build failure after merge of the perf tree

[Namhyung Kim]

Hi Arnaldo,

On Fri, Feb 23, 2024 at 12:11 PM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
>
> On Fri, Feb 23, 2024 at 04:50:47PM -0300, Arnaldo Carvalho de Melo wrote:
> > On Thu, Feb 22, 2024 at 10:06:56AM +1100, Stephen Rothwell wrote:
> > > Hi all,
> > >
> > > After merging the perf tree, today's linux-next build (native perf)
> > > failed like this:
> > >
> > > util/bpf_skel/augmented_raw_syscalls.bpf.c:329:15: error: invalid application of 'sizeof' to an incomplete type 'struct timespec64'
> > >         __u32 size = sizeof(struct timespec64);
> > >                      ^     ~~~~~~~~~~~~~~~~~~~
> > > util/bpf_skel/augmented_raw_syscalls.bpf.c:329:29: note: forward declaration of 'struct timespec64'
> > >         __u32 size = sizeof(struct timespec64);
> > >                                    ^
> > >
> > > Caused by commit
> > >
> > >   29d16de26df1 ("perf augmented_raw_syscalls.bpf: Move 'struct timespec64' to vmlinux.h")
> > >
> > > This is a ppc64 le build.
> > >
> > > I have used the perf tree from next-20240221 for today.
> >
> > Ok, finally I managed to secure a ppc64 machine to test this and
> > sometimes I reproduce just like you reported, but sometimes I can't do
> > it, didn't manage to isolate what is that makes it fail sometimes, make
> > -C tools/perf clean, nuking the O= target directory, etc, when I
> > reproduce it:
>
> So I think I see the problem, I now left the build directory with a
> previous build from torvalds/master, then switched to the
> perf-tools-branch and tried to build from there, without first removing
> the old build, it fails:
>
>   CLANG   /tmp/build/perf-tools-next/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o
> util/bpf_skel/augmented_raw_syscalls.bpf.c:329:15: error: invalid application of 'sizeof' to an incomplete type 'struct timespec64'
>   329 |         __u32 size = sizeof(struct timespec64);
>       |                      ^     ~~~~~~~~~~~~~~~~~~~
> util/bpf_skel/augmented_raw_syscalls.bpf.c:329:29: note: forward declaration of 'struct timespec64'
>   329 |         __u32 size = sizeof(struct timespec64);
>       |                                    ^
> 1 error generated.
> make[2]: *** [Makefile.perf:1161: /tmp/build/perf-tools-next/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o] Error 1
> make[1]: *** [Makefile.perf:264: sub-make] Error 2
>
>
> Because it will use what was installed before in the build dir:
>
> [acme@ibm-p9z-16-lp5 perf-tools-next]$ ls -la /tmp/build/perf-tools-next/util/bpf_skel/vmlinux.h
> -rw-r--r--. 1 acme acme 4319 Feb 23 14:59 /tmp/build/perf-tools-next/util/bpf_skel/vmlinux.h
> [acme@ibm-p9z-16-lp5 perf-tools-next]$
>
> And that one doesn't have 'struct timespec64':
>
> [acme@ibm-p9z-16-lp5 perf-tools-next]$ grep timespec64 /tmp/build/perf-tools-next/util/bpf_skel/vmlinux.h
> [acme@ibm-p9z-16-lp5 perf-tools-next]$
>
> If I remove that directory contents:
>
> [acme@ibm-p9z-16-lp5 perf-tools-next]$ rm -rf /tmp/build/perf-tools-next/
> [acme@ibm-p9z-16-lp5 perf-tools-next]$ mkdir /tmp/build/perf-tools-next/
> [acme@ibm-p9z-16-lp5 perf-tools-next]$
>
> And then try to build again:
>
> make -k O=/tmp/build/perf-tools-next/ -C tools/perf install-bin
>
> It works.
>
> I reproduced the problem on x86_64, so, on this transition period, the
> problem happens, probably we need to robustify the installation of
> tools/perf/util/bpf_skel/vmlinux/vmlinux.h in the O= target directory,
> but if you just make sure the build directory is clean before trying to
> build it, this time, it should work, wdyt?

Can we add a dependency to the minimal vmlinux.h?

Thanks,
Namhyung

---8<---
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 3cecd51b2397..33621114135e 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -1147,7 +1147,7 @@ ifeq ($(VMLINUX_H),)
   endif
 endif

-$(SKEL_OUT)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
+$(SKEL_OUT)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) $(VMLINUX_H)
 ifeq ($(VMLINUX_H),)
        $(QUIET_GEN)$(BPFTOOL) btf dump file $< format c > $@
 else