This is a note to let you know that I've just added the patch titled
bpf: Use -Wno-error in certain tests when building with GCC
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-use-wno-error-in-certain-tests-when-building-wit.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit bd5366d67aa5d67fda93b001e548d64da68927d5
Author: Jose E. Marchesi <jose.marchesi@xxxxxxxxxx>
Date: Sat Jan 27 11:07:02 2024 +0100
bpf: Use -Wno-error in certain tests when building with GCC
[ Upstream commit 646751d523587cfd7ebcf1733298ecd470879eda ]
Certain BPF selftests contain code that, albeit being legal C, trigger
warnings in GCC that cannot be disabled. This is the case for example
for the tests
progs/btf_dump_test_case_bitfields.c
progs/btf_dump_test_case_namespacing.c
progs/btf_dump_test_case_packing.c
progs/btf_dump_test_case_padding.c
progs/btf_dump_test_case_syntax.c
which contain struct type declarations inside function parameter
lists. This is problematic, because:
- The BPF selftests are built with -Werror.
- The Clang and GCC compilers sometimes differ when it comes to handle
warnings. in the handling of warnings. One compiler may emit
warnings for code that the other compiles compiles silently, and one
compiler may offer the possibility to disable certain warnings, while
the other doesn't.
In order to overcome this problem, this patch modifies the
tools/testing/selftests/bpf/Makefile in order to:
1. Enable the possibility of specifing per-source-file extra CFLAGS.
This is done by defining a make variable like:
<source-filename>-CFLAGS := <whateverflags>
And then modifying the proper Make rule in order to use these flags
when compiling <source-filename>.
2. Use the mechanism above to add -Wno-error to CFLAGS for the
following selftests:
progs/btf_dump_test_case_bitfields.c
progs/btf_dump_test_case_namespacing.c
progs/btf_dump_test_case_packing.c
progs/btf_dump_test_case_padding.c
progs/btf_dump_test_case_syntax.c
Note the corresponding -CFLAGS variables for these files are
defined only if the selftests are being built with GCC.
Note that, while compiler pragmas can generally be used to disable
particular warnings per file, this 1) is only possible for warning
that actually can be disabled in the command line, i.e. that have
-Wno-FOO options, and 2) doesn't apply to -Wno-error.
Tested in bpf-next master branch.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20240127100702.21549-1-jose.marchesi@xxxxxxxxxx
Stable-dep-of: 3ece93a4087b ("selftests/bpf: Fix wrong binary in Makefile log output")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 598cd118dfd65..397306f5cf911 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -56,6 +56,15 @@ TEST_INST_SUBDIRS := no_alu32
ifneq ($(BPF_GCC),)
TEST_GEN_PROGS += test_progs-bpf_gcc
TEST_INST_SUBDIRS += bpf_gcc
+
+# The following tests contain C code that, although technically legal,
+# triggers GCC warnings that cannot be disabled: declaration of
+# anonymous struct types in function parameter lists.
+progs/btf_dump_test_case_bitfields.c-CFLAGS := -Wno-error
+progs/btf_dump_test_case_namespacing.c-CFLAGS := -Wno-error
+progs/btf_dump_test_case_packing.c-CFLAGS := -Wno-error
+progs/btf_dump_test_case_padding.c-CFLAGS := -Wno-error
+progs/btf_dump_test_case_syntax.c-CFLAGS := -Wno-error
endif
ifneq ($(CLANG_CPUV4),)
@@ -492,7 +501,8 @@ $(TRUNNER_BPF_OBJS): $(TRUNNER_OUTPUT)/%.bpf.o: \
$(wildcard $(BPFDIR)/*.bpf.h) \
| $(TRUNNER_OUTPUT) $$(BPFOBJ)
$$(call $(TRUNNER_BPF_BUILD_RULE),$$<,$$@, \
- $(TRUNNER_BPF_CFLAGS))
+ $(TRUNNER_BPF_CFLAGS) \
+ $$($$<-CFLAGS))
$(TRUNNER_BPF_SKELS): %.skel.h: %.bpf.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
$$(call msg,GEN-SKEL,$(TRUNNER_BINARY),$$@)
