[PATCH 0/2] Fast path feature detection fixes

[PATCH 0/2] Fast path feature detection fixes

[Arnaldo Carvalho de Melo]

Hi,

	This is on top of a previous patch I sent today for libunwind
opt-in fallout, I'll continue checking if what is being enabled when
test-all.c builds is the right set of features to be declared as
detected on this fast path method.

- Arnaldo

Arnaldo Carvalho de Melo (2):
  tools build feature: Add some comments to explain the FEATURE_TESTS logic
  tools build feature: Don't set feature-libcap=1 if libcap-devel isn't available

 tools/build/Makefile.feature | 37 ++++++++++++++++++++++++++++++++++--
 tools/build/feature/Makefile |  2 +-
 2 files changed, 36 insertions(+), 3 deletions(-)

-- 
2.47.0

[PATCH 1/2] tools build feature: Add some comments to explain the FEATURE_TESTS logic

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

The tools/build/feature/test-all.c works in conjunction with the
tools/build/Makefile.feature FEATURE_TESTS_BASIC and FEATURE_TESTS_EXTRA
contents, so that if test-all.c manages to be built, we go on and
iterate all entries in FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA setting
then to 1.

To test this:

  $ rm -rf /tmp/b ; mkdir /tmp/b ; make -C tools/perf O=/tmp/b feature-dump
  $ cat /tmp/b/feature/test-all.make.output
  $ ldd /tmp/b/feature/test-all.bin
	linux-vdso.so.1 (0x00007f2a47a67000)
	libdw.so.1 => /lib64/libdw.so.1 (0x00007f2a477cf000)
	libpython3.12.so.1.0 => /lib64/libpython3.12.so.1.0 (0x00007f2a471fe000)
	libm.so.6 => /lib64/libm.so.6 (0x00007f2a4711a000)
	libtraceevent.so.1 => /lib64/libtraceevent.so.1 (0x00007f2a470f2000)
	libtracefs.so.1 => /lib64/libtracefs.so.1 (0x00007f2a470cb000)
	libcrypto.so.3 => /lib64/libcrypto.so.3 (0x00007f2a46c1b000)
	libz.so.1 => /lib64/libz.so.1 (0x00007f2a46bf8000)
	libbabeltrace-ctf.so.1 => /lib64/libbabeltrace-ctf.so.1 (0x00007f2a46bad000)
	libcapstone.so.5 => /lib64/libcapstone.so.5 (0x00007f2a464b8000)
	libopencsd_c_api.so.1 => /lib64/libopencsd_c_api.so.1 (0x00007f2a464a8000)
	libopencsd.so.1 => /lib64/libopencsd.so.1 (0x00007f2a46422000)
	libelf.so.1 => /lib64/libelf.so.1 (0x00007f2a46406000)
	libnuma.so.1 => /lib64/libnuma.so.1 (0x00007f2a463f6000)
	libslang.so.2 => /lib64/libslang.so.2 (0x00007f2a46113000)
	libperl.so.5.38 => /lib64/libperl.so.5.38 (0x00007f2a45d74000)
	libc.so.6 => /lib64/libc.so.6 (0x00007f2a45b83000)
	liblzma.so.5 => /lib64/liblzma.so.5 (0x00007f2a45b50000)
	libzstd.so.1 => /lib64/libzstd.so.1 (0x00007f2a45a91000)
	libbz2.so.1 => /lib64/libbz2.so.1 (0x00007f2a45a7b000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f2a47a69000)
	libbabeltrace.so.1 => /lib64/libbabeltrace.so.1 (0x00007f2a45a6b000)
	libpopt.so.0 => /lib64/libpopt.so.0 (0x00007f2a45a5b000)
	libuuid.so.1 => /lib64/libuuid.so.1 (0x00007f2a45a51000)
	libgmodule-2.0.so.0 => /lib64/libgmodule-2.0.so.0 (0x00007f2a45a4a000)
	libglib-2.0.so.0 => /lib64/libglib-2.0.so.0 (0x00007f2a458fa000)
	libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f2a45696000)
	libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f2a45668000)
	libcrypt.so.2 => /lib64/libcrypt.so.2 (0x00007f2a45630000)
	libpcre2-8.so.0 => /lib64/libpcre2-8.so.0 (0x00007f2a45590000)
  $ head /tmp/b/FEATURE-DUMP
  feature-backtrace=1
  feature-libdw=1
  feature-eventfd=1
  feature-fortify-source=1
  feature-get_current_dir_name=1
  feature-gettid=1
  feature-glibc=1
  feature-libbfd=1
  feature-libbfd-buildid=1
  feature-libcap=1
  $

There are inconsistencies that are being audited, as can be seen above
with the libcap case, that is not linked with test-all.bin nor is
present in test-all.c, so shouldn't be set as present. Further patches
are going to address those inconsistencies, but lets document this a bit
more to reduce the chances of this happening again.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/build/Makefile.feature | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 80563154318601ac..52600e4d33af8712 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -28,6 +28,41 @@ endef
 #   the rule that uses them - an example for that is the 'bionic'
 #   feature check. ]
 #
+# These + the ones in FEATURE_TESTS_EXTRA are included in
+# tools/build/feature/test-all.c and we try to build it all together
+# then setting all those features to '1' meaning they are all enabled.
+#
+# There are things like fortify-source that will be set to 1 because test-all
+# is built with the flags needed to test if its enabled, resulting in
+#
+#   $ rm -rf /tmp/b ; mkdir /tmp/b ; make -C tools/perf O=/tmp/b feature-dump
+#   $ grep fortify-source /tmp/b/FEATURE-DUMP
+#   feature-fortify-source=1
+#   $
+#
+#   All the others should have lines in tools/build/feature/test-all.c like:
+#
+#    #define main main_test_disassembler_init_styled
+#    # include "test-disassembler-init-styled.c"
+#    #undef main
+#
+#    #define main main_test_libzstd
+#    # include "test-libzstd.c"
+#    #undef main
+#
+#    int main(int argc, char *argv[])
+#    {
+#      main_test_disassembler_four_args();
+#      main_test_libzstd();
+#      return 0;
+#    }
+#
+#    If the sample above works, then we end up with these lines in the FEATURE-DUMP
+#    file:
+#
+#    feature-disassembler-four-args=1
+#    feature-libzstd=1
+#
 FEATURE_TESTS_BASIC :=                  \
         backtrace                       \
         libdw                           \
-- 
2.47.0

Re: [PATCH 1/2] tools build feature: Add some comments to explain the FEATURE_TESTS logic

[Ian Rogers]

On Wed, Dec 11, 2024 at 2:45 PM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>
> The tools/build/feature/test-all.c works in conjunction with the
> tools/build/Makefile.feature FEATURE_TESTS_BASIC and FEATURE_TESTS_EXTRA
> contents, so that if test-all.c manages to be built, we go on and
> iterate all entries in FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA setting
> then to 1.

nit: s/then/them/

> To test this:
>
>   $ rm -rf /tmp/b ; mkdir /tmp/b ; make -C tools/perf O=/tmp/b feature-dump
>   $ cat /tmp/b/feature/test-all.make.output
>   $ ldd /tmp/b/feature/test-all.bin
>         linux-vdso.so.1 (0x00007f2a47a67000)
>         libdw.so.1 => /lib64/libdw.so.1 (0x00007f2a477cf000)
>         libpython3.12.so.1.0 => /lib64/libpython3.12.so.1.0 (0x00007f2a471fe000)
>         libm.so.6 => /lib64/libm.so.6 (0x00007f2a4711a000)
>         libtraceevent.so.1 => /lib64/libtraceevent.so.1 (0x00007f2a470f2000)
>         libtracefs.so.1 => /lib64/libtracefs.so.1 (0x00007f2a470cb000)
>         libcrypto.so.3 => /lib64/libcrypto.so.3 (0x00007f2a46c1b000)
>         libz.so.1 => /lib64/libz.so.1 (0x00007f2a46bf8000)
>         libbabeltrace-ctf.so.1 => /lib64/libbabeltrace-ctf.so.1 (0x00007f2a46bad000)
>         libcapstone.so.5 => /lib64/libcapstone.so.5 (0x00007f2a464b8000)
>         libopencsd_c_api.so.1 => /lib64/libopencsd_c_api.so.1 (0x00007f2a464a8000)
>         libopencsd.so.1 => /lib64/libopencsd.so.1 (0x00007f2a46422000)
>         libelf.so.1 => /lib64/libelf.so.1 (0x00007f2a46406000)
>         libnuma.so.1 => /lib64/libnuma.so.1 (0x00007f2a463f6000)
>         libslang.so.2 => /lib64/libslang.so.2 (0x00007f2a46113000)
>         libperl.so.5.38 => /lib64/libperl.so.5.38 (0x00007f2a45d74000)
>         libc.so.6 => /lib64/libc.so.6 (0x00007f2a45b83000)
>         liblzma.so.5 => /lib64/liblzma.so.5 (0x00007f2a45b50000)
>         libzstd.so.1 => /lib64/libzstd.so.1 (0x00007f2a45a91000)
>         libbz2.so.1 => /lib64/libbz2.so.1 (0x00007f2a45a7b000)
>         /lib64/ld-linux-x86-64.so.2 (0x00007f2a47a69000)
>         libbabeltrace.so.1 => /lib64/libbabeltrace.so.1 (0x00007f2a45a6b000)
>         libpopt.so.0 => /lib64/libpopt.so.0 (0x00007f2a45a5b000)
>         libuuid.so.1 => /lib64/libuuid.so.1 (0x00007f2a45a51000)
>         libgmodule-2.0.so.0 => /lib64/libgmodule-2.0.so.0 (0x00007f2a45a4a000)
>         libglib-2.0.so.0 => /lib64/libglib-2.0.so.0 (0x00007f2a458fa000)
>         libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f2a45696000)
>         libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f2a45668000)
>         libcrypt.so.2 => /lib64/libcrypt.so.2 (0x00007f2a45630000)
>         libpcre2-8.so.0 => /lib64/libpcre2-8.so.0 (0x00007f2a45590000)
>   $ head /tmp/b/FEATURE-DUMP
>   feature-backtrace=1
>   feature-libdw=1
>   feature-eventfd=1
>   feature-fortify-source=1
>   feature-get_current_dir_name=1
>   feature-gettid=1
>   feature-glibc=1
>   feature-libbfd=1
>   feature-libbfd-buildid=1
>   feature-libcap=1
>   $
>
> There are inconsistencies that are being audited, as can be seen above
> with the libcap case, that is not linked with test-all.bin nor is
> present in test-all.c, so shouldn't be set as present. Further patches
> are going to address those inconsistencies, but lets document this a bit
> more to reduce the chances of this happening again.
>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: James Clark <james.clark@linaro.org>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/build/Makefile.feature | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
>
> diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
> index 80563154318601ac..52600e4d33af8712 100644
> --- a/tools/build/Makefile.feature
> +++ b/tools/build/Makefile.feature
> @@ -28,6 +28,41 @@ endef
>  #   the rule that uses them - an example for that is the 'bionic'
>  #   feature check. ]
>  #
> +# These + the ones in FEATURE_TESTS_EXTRA are included in
> +# tools/build/feature/test-all.c and we try to build it all together
> +# then setting all those features to '1' meaning they are all enabled.
> +#
> +# There are things like fortify-source that will be set to 1 because test-all
> +# is built with the flags needed to test if its enabled, resulting in
> +#
> +#   $ rm -rf /tmp/b ; mkdir /tmp/b ; make -C tools/perf O=/tmp/b feature-dump
> +#   $ grep fortify-source /tmp/b/FEATURE-DUMP
> +#   feature-fortify-source=1
> +#   $
> +#
> +#   All the others should have lines in tools/build/feature/test-all.c like:
> +#
> +#    #define main main_test_disassembler_init_styled
> +#    # include "test-disassembler-init-styled.c"
> +#    #undef main
> +#
> +#    #define main main_test_libzstd
> +#    # include "test-libzstd.c"
> +#    #undef main
> +#
> +#    int main(int argc, char *argv[])
> +#    {
> +#      main_test_disassembler_four_args();
> +#      main_test_libzstd();
> +#      return 0;
> +#    }
> +#
> +#    If the sample above works, then we end up with these lines in the FEATURE-DUMP
> +#    file:
> +#
> +#    feature-disassembler-four-args=1
> +#    feature-libzstd=1
> +#
>  FEATURE_TESTS_BASIC :=                  \
>          backtrace                       \
>          libdw                           \
> --
> 2.47.0
>

[PATCH 2/2] tools build feature: Don't set feature-libcap=1 if libcap-devel isn't available

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

libcap isn't tested in the tools/build/feature/test-all.c fast path
feature detection process, so don't set it as available if test-all
manages to build.

There are other users of this feature detection mechanism, and they
explicitely ask for libcap to be tested, so are not affected by this
patch, for instance, with this patch in place:

  $ make -C tools/bpf/bpftool/ clean
  <SNIP>
  make: Leaving directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
  ⬢ [acme@toolbox perf-tools-next]$ make -C tools/bpf/bpftool/
  make: Entering directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'

  Auto-detecting system features:
  ...                         clang-bpf-co-re: [ on  ]
  ...                                    llvm: [ on  ]
  ...                                  libcap: [ on  ]
  ...                                  libbfd: [ on  ]
  ...                             libelf-zstd: [ on  ]
  <SNIP>
    LINK    bpftool
  make: Leaving directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
  $
  $ sudo rpm -e libcap-devel
  $ make -C tools/bpf/bpftool/
  <SNIP>
  make: Entering directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'

  Auto-detecting system features:
  ...                         clang-bpf-co-re: [ on  ]
  ...                                    llvm: [ on  ]
  ...                                  libcap: [ OFF ]
  ...                                  libbfd: [ on  ]
  ...                             libelf-zstd: [ on  ]

  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/build/Makefile.feature | 2 --
 tools/build/feature/Makefile | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 52600e4d33af8712..e25cdb7db40e3f3d 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -73,7 +73,6 @@ FEATURE_TESTS_BASIC :=                  \
         glibc                           \
         libbfd                          \
         libbfd-buildid			\
-        libcap                          \
         libelf                          \
         libelf-getphdrnum               \
         libelf-gelf_getnote             \
@@ -150,7 +149,6 @@ FEATURE_DISPLAY ?=              \
          glibc                  \
          libbfd                 \
          libbfd-buildid		\
-         libcap                 \
          libelf                 \
          libnuma                \
          numa_num_possible_cpus \
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 043dfd00fce72d8f..cbf751b6f0f76225 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -110,7 +110,7 @@ all: $(FILES)
 __BUILD = $(CC) $(CFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
   BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1
   BUILD_BFD = $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl
-  BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd -lcap
+  BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd
 
 __BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
   BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1
-- 
2.47.0

Re: [PATCH 2/2] tools build feature: Don't set feature-libcap=1 if libcap-devel isn't available

[Ian Rogers]

On Wed, Dec 11, 2024 at 2:45 PM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>
> libcap isn't tested in the tools/build/feature/test-all.c fast path
> feature detection process, so don't set it as available if test-all
> manages to build.
>
> There are other users of this feature detection mechanism, and they
> explicitely ask for libcap to be tested, so are not affected by this
> patch, for instance, with this patch in place:
>
>   $ make -C tools/bpf/bpftool/ clean
>   <SNIP>
>   make: Leaving directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
>   ⬢ [acme@toolbox perf-tools-next]$ make -C tools/bpf/bpftool/
>   make: Entering directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
>
>   Auto-detecting system features:
>   ...                         clang-bpf-co-re: [ on  ]
>   ...                                    llvm: [ on  ]
>   ...                                  libcap: [ on  ]
>   ...                                  libbfd: [ on  ]
>   ...                             libelf-zstd: [ on  ]
>   <SNIP>
>     LINK    bpftool
>   make: Leaving directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
>   $
>   $ sudo rpm -e libcap-devel
>   $ make -C tools/bpf/bpftool/
>   <SNIP>
>   make: Entering directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
>
>   Auto-detecting system features:
>   ...                         clang-bpf-co-re: [ on  ]
>   ...                                    llvm: [ on  ]
>   ...                                  libcap: [ OFF ]
>   ...                                  libbfd: [ on  ]
>   ...                             libelf-zstd: [ on  ]
>
>   $
>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: James Clark <james.clark@linaro.org>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Quentin Monnet <qmo@kernel.org>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

Re: [PATCH 2/2] tools build feature: Don't set feature-libcap=1 if libcap-devel isn't available

[Quentin Monnet]

2024-12-11 20:25 UTC-0800 ~ Ian Rogers <irogers@google.com>
> On Wed, Dec 11, 2024 at 2:45 PM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
>>
>> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>>
>> libcap isn't tested in the tools/build/feature/test-all.c fast path
>> feature detection process, so don't set it as available if test-all
>> manages to build.
>>
>> There are other users of this feature detection mechanism, and they
>> explicitely ask for libcap to be tested, so are not affected by this
>> patch, for instance, with this patch in place:
>>
>>   $ make -C tools/bpf/bpftool/ clean
>>   <SNIP>
>>   make: Leaving directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
>>   ⬢ [acme@toolbox perf-tools-next]$ make -C tools/bpf/bpftool/
>>   make: Entering directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
>>
>>   Auto-detecting system features:
>>   ...                         clang-bpf-co-re: [ on  ]
>>   ...                                    llvm: [ on  ]
>>   ...                                  libcap: [ on  ]
>>   ...                                  libbfd: [ on  ]
>>   ...                             libelf-zstd: [ on  ]
>>   <SNIP>
>>     LINK    bpftool
>>   make: Leaving directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
>>   $
>>   $ sudo rpm -e libcap-devel
>>   $ make -C tools/bpf/bpftool/
>>   <SNIP>
>>   make: Entering directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
>>
>>   Auto-detecting system features:
>>   ...                         clang-bpf-co-re: [ on  ]
>>   ...                                    llvm: [ on  ]
>>   ...                                  libcap: [ OFF ]
>>   ...                                  libbfd: [ on  ]
>>   ...                             libelf-zstd: [ on  ]
>>
>>   $
>>
>> Cc: Adrian Hunter <adrian.hunter@intel.com>
>> Cc: Ian Rogers <irogers@google.com>
>> Cc: James Clark <james.clark@linaro.org>
>> Cc: Jiri Olsa <jolsa@kernel.org>
>> Cc: Kan Liang <kan.liang@linux.intel.com>
>> Cc: Namhyung Kim <namhyung@kernel.org>
>> Cc: Quentin Monnet <qmo@kernel.org>
>> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> Reviewed-by: Ian Rogers <irogers@google.com>


Acked-by: Quentin Monnet <qmo@kernel.org>

Thanks Arnaldo for checking the bpftool build :)
Quentin

Re: [PATCH 2/2] tools build feature: Don't set feature-libcap=1 if libcap-devel isn't available

[Arnaldo Carvalho de Melo]

On Thu, Dec 12, 2024 at 10:16:38AM +0000, Quentin Monnet wrote:
> 2024-12-11 20:25 UTC-0800 ~ Ian Rogers <irogers@google.com>
> > On Wed, Dec 11, 2024 at 2:45 PM Arnaldo Carvalho de Melo
> > <acme@kernel.org> wrote:
> >>
> >> From: Arnaldo Carvalho de Melo <acme@redhat.com>
> >>
> >> libcap isn't tested in the tools/build/feature/test-all.c fast path
> >> feature detection process, so don't set it as available if test-all
> >> manages to build.
> >>
> >> There are other users of this feature detection mechanism, and they
> >> explicitely ask for libcap to be tested, so are not affected by this
> >> patch, for instance, with this patch in place:
> >>
> >>   $ make -C tools/bpf/bpftool/ clean
> >>   <SNIP>
> >>   make: Leaving directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
> >>   ⬢ [acme@toolbox perf-tools-next]$ make -C tools/bpf/bpftool/
> >>   make: Entering directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
> >>
> >>   Auto-detecting system features:
> >>   ...                         clang-bpf-co-re: [ on  ]
> >>   ...                                    llvm: [ on  ]
> >>   ...                                  libcap: [ on  ]
> >>   ...                                  libbfd: [ on  ]
> >>   ...                             libelf-zstd: [ on  ]
> >>   <SNIP>
> >>     LINK    bpftool
> >>   make: Leaving directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
> >>   $
> >>   $ sudo rpm -e libcap-devel
> >>   $ make -C tools/bpf/bpftool/
> >>   <SNIP>
> >>   make: Entering directory '/home/acme/git/perf-tools-next/tools/bpf/bpftool'
> >>
> >>   Auto-detecting system features:
> >>   ...                         clang-bpf-co-re: [ on  ]
> >>   ...                                    llvm: [ on  ]
> >>   ...                                  libcap: [ OFF ]
> >>   ...                                  libbfd: [ on  ]
> >>   ...                             libelf-zstd: [ on  ]
> >>
> >>   $
> >>
> >> Cc: Adrian Hunter <adrian.hunter@intel.com>
> >> Cc: Ian Rogers <irogers@google.com>
> >> Cc: James Clark <james.clark@linaro.org>
> >> Cc: Jiri Olsa <jolsa@kernel.org>
> >> Cc: Kan Liang <kan.liang@linux.intel.com>
> >> Cc: Namhyung Kim <namhyung@kernel.org>
> >> Cc: Quentin Monnet <qmo@kernel.org>
> >> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> > 
> > Reviewed-by: Ian Rogers <irogers@google.com>
> 
> 
> Acked-by: Quentin Monnet <qmo@kernel.org>
> 
> Thanks Arnaldo for checking the bpftool build :)

Thanks! Added to the cset.

- Arnaldo