Various compilation errors happen when BPF programs in selftests/bpf
are built with GCC BPF. For more details see the discussion at [1].
The changes only affect test_progs-bpf_gcc, which is built only if
BPF_GCC is set:
* Pass -std=gnu17 to gcc in order to avoid errors on bool types
declarations in vmlinux.h
* Pass -fno-strict-aliasing for tests that trigger uninitialized
variable warning on BPF_RAW_INSNS [2]
[1] https://lore.kernel.org/bpf/EYcXjcKDCJY7Yb0GGtAAb7nLKPEvrgWdvWpuNzXm2qi6rYMZDixKv5KwfVVMBq17V55xyC-A1wIjrqG3aw-Imqudo9q9X7D7nLU2gWgbN0w=@pm.me/
[2] https://lore.kernel.org/bpf/87pll3c8bt.fsf@xxxxxxxxxx/
CC: Jose E. Marchesi <jose.marchesi@xxxxxxxxxx>
Signed-off-by: Ihor Solodrai <ihor.solodrai@xxxxx>
---
v1: https://lore.kernel.org/bpf/20250104001751.1869849-1-ihor.solodrai@xxxxx/
tools/testing/selftests/bpf/Makefile | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index eb4d21651aa7..b043791fe6db 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -69,6 +69,10 @@ progs/timer_crash.c-CFLAGS := -fno-strict-aliasing
progs/test_global_func9.c-CFLAGS := -fno-strict-aliasing
progs/verifier_nocsr.c-CFLAGS := -fno-strict-aliasing
+# Uninitialized variable warning on BPF_RAW_INSN
+progs/verifier_bpf_fastcall.c-CFLAGS := -fno-strict-aliasing
+progs/verifier_search_pruning.c-CFLAGS := -fno-strict-aliasing
+
# Some utility functions use LLVM libraries
jit_disasm_helpers.c-CFLAGS = $(LLVM_CFLAGS)
@@ -507,7 +511,7 @@ endef
# Build BPF object using GCC
define GCC_BPF_BUILD_RULE
$(call msg,GCC-BPF,$4,$2)
- $(Q)$(BPF_GCC) $3 -DBPF_NO_PRESERVE_ACCESS_INDEX -Wno-attributes -O2 -c $1 -o $2
+ $(Q)$(BPF_GCC) $3 -DBPF_NO_PRESERVE_ACCESS_INDEX -Wno-attributes -O2 -std=gnu17 -c $1 -o $2
endef
SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c
--
2.47.1
