From: Zhao Mengmeng Similar to commit 835a50753579 ("selftests/bpf: Add -fms-extensions to bpf build flags") and commit 639f58a0f480 ("bpftool: Fix build warnings due to MS extensions") The kernel is now built with -fms-extensions, therefore generated vmlinux.h contains types like: struct aes_key { struct aes_enckey; union aes_invkey_arch inv_k; }; struct ns_common { ... union { struct ns_tree; struct callback_head ns_rcu; }; }; Which raise warning like below when building scx scheduler: tools/sched_ext/build/include/vmlinux.h:50533:3: warning: declaration does not declare anything [-Wmissing-declarations] 50533 | struct ns_tree; | ^ Fix it by using -fms-extensions and -Wno-microsoft-anon-tag flags to build bpf programs that #include "vmlinux.h" Signed-off-by: Zhao Mengmeng --- tools/sched_ext/Makefile | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/sched_ext/Makefile b/tools/sched_ext/Makefile index 47ad7444677e..21554f089692 100644 --- a/tools/sched_ext/Makefile +++ b/tools/sched_ext/Makefile @@ -122,6 +122,8 @@ BPF_CFLAGS = -g -D__TARGET_ARCH_$(SRCARCH) \ -I../../include \ $(call get_sys_includes,$(CLANG)) \ -Wall -Wno-compare-distinct-pointer-types \ + -Wno-microsoft-anon-tag \ + -fms-extensions \ -O2 -mcpu=v3 # sort removes libbpf duplicates when not cross-building -- 2.43.0 From: Zhao Mengmeng Similar to commit 835a50753579 ("selftests/bpf: Add -fms-extensions to bpf build flags") and commit 639f58a0f480 ("bpftool: Fix build warnings due to MS extensions") Fix "declaration does not declare anything" warning by using -fms-extensions and -Wno-microsoft-anon-tag flags to build bpf programs that #include "vmlinux.h" Signed-off-by: Zhao Mengmeng --- tools/testing/selftests/sched_ext/Makefile | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile index 2815a875bde2..a3bbe2c7911b 100644 --- a/tools/testing/selftests/sched_ext/Makefile +++ b/tools/testing/selftests/sched_ext/Makefile @@ -93,6 +93,8 @@ BPF_CFLAGS = -g -D__TARGET_ARCH_$(SRCARCH) \ $(CLANG_SYS_INCLUDES) \ -Wall -Wno-compare-distinct-pointer-types \ -Wno-incompatible-function-pointer-types \ + -Wno-microsoft-anon-tag \ + -fms-extensions \ -O2 -mcpu=v3 # sort removes libbpf duplicates when not cross-building -- 2.43.0 From: Zhao Mengmeng When compiling sched_ext selftests using clang 17.0.6, it raised compiler crash and build error: Error at line 68: Unsupport signed division for DAG: 0x55b2f9a60240: i64 = sdiv 0x55b2f9a609b0, Constant:i64<100>, peek_dsq.bpf.c:68:25 @[ peek_dsq.bpf.c:95:4 @[ peek_dsq.bpf.c:169:8 @[ peek _dsq.bpf.c:140:6 ] ] ]Please convert to unsigned div/mod After digging, it's not a compiler error, clang supported Signed division only when using -mcpu=v4, while we use -mcpu=v3 currently, the better way is to use unsigned div, see [1] for details. [1] https://github.com/llvm/llvm-project/issues/70433 Signed-off-by: Zhao Mengmeng --- tools/testing/selftests/sched_ext/peek_dsq.bpf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/sched_ext/peek_dsq.bpf.c b/tools/testing/selftests/sched_ext/peek_dsq.bpf.c index a3faf5bb49d6..784f2f6c1af9 100644 --- a/tools/testing/selftests/sched_ext/peek_dsq.bpf.c +++ b/tools/testing/selftests/sched_ext/peek_dsq.bpf.c @@ -58,14 +58,14 @@ static void record_peek_result(long pid) { u32 slot_key; long *slot_pid_ptr; - int ix; + u32 ix; if (pid <= 0) return; /* Find an empty slot or one with the same PID */ bpf_for(ix, 0, 10) { - slot_key = (pid + ix) % MAX_SAMPLES; + slot_key = ((u64)pid + ix) % MAX_SAMPLES; slot_pid_ptr = bpf_map_lookup_elem(&peek_results, &slot_key); if (!slot_pid_ptr) continue; -- 2.43.0