Commit 760ebc45746b ("perf lock contention: Add empty 'struct rq' to
satisfy libbpf 'runqueue' type verification") inadvertently created a
declaration of 'struct rq' that conflicted with a generated
vmlinux.h's:

```
util/bpf_skel/lock_contention.bpf.c:419:8: error: redefinition of 'rq'
struct rq {};
       ^
/tmp/perf/util/bpf_skel/.tmp/../vmlinux.h:45630:8: note: previous definition is here
struct rq {
       ^
1 error generated.
```

Fix the issue by moving the declaration to vmlinux.h. So this can't
happen again, bring back build support for generating vmlinux.h then
add build tests.

v4. Rebase and add Namhyung and Jiri's acked-by.
v3. Address Namhyung's comments on filtering ELF files with readelf.
v2. Rebase on perf-tools-next. Add Andrii's acked-by. Add patch to
    filter out kernels that lack a .BTF section and cause the build to
    break.

Ian Rogers (4):
  perf build: Add ability to build with a generated vmlinux.h
  perf bpf: Move the declaration of struct rq
  perf test: Add build tests for BUILD_BPF_SKEL
  perf build: Filter out BTF sources without a .BTF section

 tools/perf/Makefile.config                    |  4 ++
 tools/perf/Makefile.perf                      | 39 ++++++++++++++++++-
 tools/perf/tests/make                         |  4 ++
 tools/perf/util/bpf_skel/.gitignore           |  1 +
 .../perf/util/bpf_skel/lock_contention.bpf.c  |  2 -
 .../util/bpf_skel/{ => vmlinux}/vmlinux.h     | 10 +++++
 6 files changed, 57 insertions(+), 3 deletions(-)
 rename tools/perf/util/bpf_skel/{ => vmlinux}/vmlinux.h (90%)

-- 
2.41.0.162.gfafddb0af9-goog

On Thu, Jun 22, 2023 at 9:14 PM Ian Rogers <irogers@google.com> wrote:
>
> Commit 760ebc45746b ("perf lock contention: Add empty 'struct rq' to
> satisfy libbpf 'runqueue' type verification") inadvertently created a
> declaration of 'struct rq' that conflicted with a generated
> vmlinux.h's:
>
> ```
> util/bpf_skel/lock_contention.bpf.c:419:8: error: redefinition of 'rq'
> struct rq {};
>        ^
> /tmp/perf/util/bpf_skel/.tmp/../vmlinux.h:45630:8: note: previous definition is here
> struct rq {
>        ^
> 1 error generated.
> ```
>
> Fix the issue by moving the declaration to vmlinux.h. So this can't
> happen again, bring back build support for generating vmlinux.h then
> add build tests.
>
> v4. Rebase and add Namhyung and Jiri's acked-by.
> v3. Address Namhyung's comments on filtering ELF files with readelf.
> v2. Rebase on perf-tools-next. Add Andrii's acked-by. Add patch to
>     filter out kernels that lack a .BTF section and cause the build to
>     break.
>
> Ian Rogers (4):
>   perf build: Add ability to build with a generated vmlinux.h
>   perf bpf: Move the declaration of struct rq
>   perf test: Add build tests for BUILD_BPF_SKEL
>   perf build: Filter out BTF sources without a .BTF section

Thanks,  I'll take them with the following change.

Namhyung


---
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index b1e62a621f92..90f0eaf179fd 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -132,6 +132,8 @@ include ../scripts/utilities.mak
 # Define EXTRA_TESTS to enable building extra tests useful mainly to perf
 # developers, such as:
 #      x86 instruction decoder - new instructions test
+#
+# Define GEN_VMLINUX_H to generate vmlinux.h from the BTF.

 # As per kernel Makefile, avoid funny character set dependencies
 unexport LC_ALL

On Fri, Jun 23, 2023 at 5:41 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> On Thu, Jun 22, 2023 at 9:14 PM Ian Rogers <irogers@google.com> wrote:
> >
> > Commit 760ebc45746b ("perf lock contention: Add empty 'struct rq' to
> > satisfy libbpf 'runqueue' type verification") inadvertently created a
> > declaration of 'struct rq' that conflicted with a generated
> > vmlinux.h's:
> >
> > ```
> > util/bpf_skel/lock_contention.bpf.c:419:8: error: redefinition of 'rq'
> > struct rq {};
> >        ^
> > /tmp/perf/util/bpf_skel/.tmp/../vmlinux.h:45630:8: note: previous definition is here
> > struct rq {
> >        ^
> > 1 error generated.
> > ```
> >
> > Fix the issue by moving the declaration to vmlinux.h. So this can't
> > happen again, bring back build support for generating vmlinux.h then
> > add build tests.
> >
> > v4. Rebase and add Namhyung and Jiri's acked-by.
> > v3. Address Namhyung's comments on filtering ELF files with readelf.
> > v2. Rebase on perf-tools-next. Add Andrii's acked-by. Add patch to
> >     filter out kernels that lack a .BTF section and cause the build to
> >     break.
> >
> > Ian Rogers (4):
> >   perf build: Add ability to build with a generated vmlinux.h
> >   perf bpf: Move the declaration of struct rq
> >   perf test: Add build tests for BUILD_BPF_SKEL
> >   perf build: Filter out BTF sources without a .BTF section
>
> Thanks,  I'll take them with the following change.

Applied to perf-tools-next with it, thanks!