Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Changbin Du <changbin.du@gmail.com>
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Quentin Monnet <quentin@isovalent.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Shuah Khan <shuah@kernel.org>
Cc:     Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Mykola Lysenko <mykolal@fb.com>,
        linux-perf-users@vger.kernel.org, linux-kselftest@vger.kernel.org,
        Changbin Du <changbin.du@gmail.com>
Subject: [PATCH 2/2] makefiles: do not generate empty vmlinux.h
Date:   Sat, 26 Nov 2022 19:11:47 +0800
Message-Id: <20221126111147.199366-3-changbin.du@gmail.com>
In-Reply-To: <20221126111147.199366-1-changbin.du@gmail.com>
References: <20221126111147.199366-1-changbin.du@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Remove the empty vmlinux.h if bpftool failed to dump btf info.
The emptry vmlinux.h can hide real error when reading output
of make.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
---
 samples/bpf/Makefile                 | 2 +-
 tools/bpf/bpftool/Makefile           | 2 +-
 tools/bpf/runqslower/Makefile        | 2 +-
 tools/perf/Makefile.perf             | 2 +-
 tools/testing/selftests/bpf/Makefile | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 727da3c5879b..ab4788b4883e 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -362,7 +362,7 @@ ifeq ($(VMLINUX_BTF),)
 	$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)",\
 		build the kernel or set VMLINUX_BTF or VMLINUX_H variable)
 endif
-	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
+	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@ || { rm $@; exit 1; }
 else
 	$(Q)cp "$(VMLINUX_H)" $@
 endif
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 4a95c017ad4c..d9d6f890884c 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -177,7 +177,7 @@ BUILD_BPF_SKELS := 1
 
 $(OUTPUT)vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL_BOOTSTRAP)
 ifeq ($(VMLINUX_H),)
-	$(QUIET_GEN)$(BPFTOOL_BOOTSTRAP) btf dump file $< format c > $@
+	$(QUIET_GEN)$(BPFTOOL_BOOTSTRAP) btf dump file $< format c > $@ || { rm $@; exit 1; }
 else
 	$(Q)cp "$(VMLINUX_H)" $@
 endif
diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile
index 8b3d87b82b7a..2d7911f4666b 100644
--- a/tools/bpf/runqslower/Makefile
+++ b/tools/bpf/runqslower/Makefile
@@ -77,7 +77,7 @@ ifeq ($(VMLINUX_H),)
 			"specify its location." >&2;			       \
 		exit 1;\
 	fi
-	$(QUIET_GEN)$(BPFTOOL) btf dump file $(VMLINUX_BTF_PATH) format c > $@
+	$(QUIET_GEN)$(BPFTOOL) btf dump file $(VMLINUX_BTF_PATH) format c > $@ || { rm $@; exit 1; }
 else
 	$(Q)cp "$(VMLINUX_H)" $@
 endif
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index a432e59afc42..0546d408aa4e 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -1064,7 +1064,7 @@ VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
 
 $(SKEL_OUT)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
 ifeq ($(VMLINUX_H),)
-	$(QUIET_GEN)$(BPFTOOL) btf dump file $< format c > $@
+	$(QUIET_GEN)$(BPFTOOL) btf dump file $< format c > $@ || { rm $@; exit 1; }
 else
 	$(Q)cp "$(VMLINUX_H)" $@
 endif
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index e6cf21fad69f..9aa2475b4ac6 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -284,7 +284,7 @@ endif
 $(INCLUDE_DIR)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR)
 ifeq ($(VMLINUX_H),)
 	$(call msg,GEN,,$@)
-	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
+	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@ || { rm $@; exit 1; }
 else
 	$(call msg,CP,,$@)
 	$(Q)cp "$(VMLINUX_H)" $@
-- 
2.37.2