kernel-patches · theihor · Jan 16, 2025 · Jan 16, 2025
diff --git a/ci/diffs/2001-selftests-bpf-add-fno-strict-aliasing-to-BPF_CFLAGS.patch b/ci/diffs/2001-selftests-bpf-add-fno-strict-aliasing-to-BPF_CFLAGS.patch
@@ -0,0 +1,75 @@
+From f44275e7155dc310d36516fc25be503da099781c Mon Sep 17 00:00:00 2001
+From: Ihor Solodrai <ihor.solodrai@pm.me>
+Date: Mon, 6 Jan 2025 20:17:31 +0000
+Subject: [PATCH] selftests/bpf: add -fno-strict-aliasing to BPF_CFLAGS
+
+Following the discussion at [1], set -fno-strict-aliasing flag for all
+BPF object build rules. Remove now unnecessary <test>-CFLAGS variables.
+
+[1] https://lore.kernel.org/bpf/20250106185447.951609-1-ihor.solodrai@pm.me/
+
+CC: Jose E. Marchesi <jose.marchesi@oracle.com>
+Signed-off-by: Ihor Solodrai <ihor.solodrai@pm.me>
+Acked-by: Eduard Zingerman <eddyz87@gmail.com>
+Link: https://lore.kernel.org/r/20250106201728.1219791-1-ihor.solodrai@pm.me
+Signed-off-by: Alexei Starovoitov <ast@kernel.org>
+---
+ tools/testing/selftests/bpf/Makefile | 28 +---------------------------
+ 1 file changed, 1 insertion(+), 27 deletions(-)
+
+diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
+index eb4d21651aa7..d5be2f94deef 100644
+--- a/tools/testing/selftests/bpf/Makefile
++++ b/tools/testing/selftests/bpf/Makefile
+@@ -54,21 +54,6 @@ PCAP_LIBS	:= $(shell $(PKG_CONFIG) --libs libpcap 2>/dev/null)
+ LDLIBS += $(PCAP_LIBS)
+ CFLAGS += $(PCAP_CFLAGS)
+
+-# The following tests perform type punning and they may break strict
+-# aliasing rules, which are exploited by both GCC and clang by default
+-# while optimizing.  This can lead to broken programs.
+-progs/bind4_prog.c-CFLAGS := -fno-strict-aliasing
+-progs/bind6_prog.c-CFLAGS := -fno-strict-aliasing
+-progs/dynptr_fail.c-CFLAGS := -fno-strict-aliasing
+-progs/linked_list_fail.c-CFLAGS := -fno-strict-aliasing
+-progs/map_kptr_fail.c-CFLAGS := -fno-strict-aliasing
+-progs/syscall.c-CFLAGS := -fno-strict-aliasing
+-progs/test_pkt_md_access.c-CFLAGS := -fno-strict-aliasing
+-progs/test_sk_lookup.c-CFLAGS := -fno-strict-aliasing
+-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
+-
+ # Some utility functions use LLVM libraries
+ jit_disasm_helpers.c-CFLAGS = $(LLVM_CFLAGS)
+
+@@ -103,18 +88,6 @@ progs/btf_dump_test_case_packing.c-bpf_gcc-CFLAGS := -Wno-error
+ progs/btf_dump_test_case_padding.c-bpf_gcc-CFLAGS := -Wno-error
+ progs/btf_dump_test_case_syntax.c-bpf_gcc-CFLAGS := -Wno-error
+
+-# The following tests do type-punning, via the __imm_insn macro, from
+-# `struct bpf_insn' to long and then uses the value.  This triggers an
+-# "is used uninitialized" warning in GCC due to strict-aliasing
+-# rules.
+-progs/verifier_ref_tracking.c-bpf_gcc-CFLAGS := -fno-strict-aliasing
+-progs/verifier_unpriv.c-bpf_gcc-CFLAGS := -fno-strict-aliasing
+-progs/verifier_cgroup_storage.c-bpf_gcc-CFLAGS := -fno-strict-aliasing
+-progs/verifier_ld_ind.c-bpf_gcc-CFLAGS := -fno-strict-aliasing
+-progs/verifier_map_ret_val.c-bpf_gcc-CFLAGS := -fno-strict-aliasing
+-progs/verifier_spill_fill.c-bpf_gcc-CFLAGS := -fno-strict-aliasing
+-progs/verifier_subprog_precision.c-bpf_gcc-CFLAGS := -fno-strict-aliasing
+-progs/verifier_uninit.c-bpf_gcc-CFLAGS := -fno-strict-aliasing
+ endif
+
+ ifneq ($(CLANG_CPUV4),)
+@@ -474,6 +447,7 @@ CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
+ BPF_CFLAGS = -g -Wall -Werror -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN)	\
+ 	     -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR)			\
+ 	     -I$(abspath $(OUTPUT)/../usr/include)			\
++	     -fno-strict-aliasing 					\
+ 	     -Wno-compare-distinct-pointer-types
+ # TODO: enable me -Wsign-compare
+
+-- 
+2.47.1
+
diff --git a/ci/diffs/2002-selftests-bpf-add-std-gnu11-to-BPF_CFLAGS-and-CFLAGS.patch b/ci/diffs/2002-selftests-bpf-add-std-gnu11-to-BPF_CFLAGS-and-CFLAGS.patch
@@ -0,0 +1,63 @@
+From bab18c7db44d3aa6c84450095451580922359c7a Mon Sep 17 00:00:00 2001
+From: Ihor Solodrai <ihor.solodrai@pm.me>
+Date: Tue, 7 Jan 2025 23:58:18 +0000
+Subject: [PATCH] selftests/bpf: add -std=gnu11 to BPF_CFLAGS and CFLAGS
+
+Latest versions of GCC BPF use C23 standard by default. This causes
+compilation errors in vmlinux.h due to bool types declarations.
+
+Add -std=gnu11 to BPF_CFLAGS and CFLAGS. This aligns with the version
+of the standard used when building the kernel currently [1].
+
+For more details see the discussions at [2] and [3].
+
+[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Makefile#n465
+[2] https://lore.kernel.org/bpf/EYcXjcKDCJY7Yb0GGtAAb7nLKPEvrgWdvWpuNzXm2qi6rYMZDixKv5KwfVVMBq17V55xyC-A1wIjrqG3aw-Imqudo9q9X7D7nLU2gWgbN0w=@pm.me/
+[3] https://lore.kernel.org/bpf/20250106202715.1232864-1-ihor.solodrai@pm.me/
+
+CC: Jose E. Marchesi <jose.marchesi@oracle.com>
+Signed-off-by: Ihor Solodrai <ihor.solodrai@pm.me>
+Link: https://lore.kernel.org/r/20250107235813.2964472-1-ihor.solodrai@pm.me
+Signed-off-by: Alexei Starovoitov <ast@kernel.org>
+---
+ tools/testing/selftests/bpf/Makefile | 8 ++++++--
+ 1 file changed, 6 insertions(+), 2 deletions(-)
+
+diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
+index d5be2f94deef..ea9cee5de0f8 100644
+--- a/tools/testing/selftests/bpf/Makefile
++++ b/tools/testing/selftests/bpf/Makefile
+@@ -41,7 +41,7 @@ srctree := $(patsubst %/,%,$(dir $(srctree)))
+ srctree := $(patsubst %/,%,$(dir $(srctree)))
+ endif
+
+-CFLAGS += -g $(OPT_FLAGS) -rdynamic					\
++CFLAGS += -g $(OPT_FLAGS) -rdynamic -std=gnu11				\
+ 	  -Wall -Werror -fno-omit-frame-pointer				\
+ 	  $(GENFLAGS) $(SAN_CFLAGS) $(LIBELF_CFLAGS)			\
+ 	  -I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR)		\
+@@ -447,6 +447,7 @@ CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
+ BPF_CFLAGS = -g -Wall -Werror -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN)	\
+ 	     -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR)			\
+ 	     -I$(abspath $(OUTPUT)/../usr/include)			\
++	     -std=gnu11		 					\
+ 	     -fno-strict-aliasing 					\
+ 	     -Wno-compare-distinct-pointer-types
+ # TODO: enable me -Wsign-compare
+@@ -787,9 +788,12 @@ $(OUTPUT)/xdp_features: xdp_features.c $(OUTPUT)/network_helpers.o $(OUTPUT)/xdp
+ 	$(Q)$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
+
+ # Make sure we are able to include and link libbpf against c++.
++CXXFLAGS += $(CFLAGS)
++CXXFLAGS := $(subst -D_GNU_SOURCE=,,$(CXXFLAGS))
++CXXFLAGS := $(subst -std=gnu11,-std=gnu++11,$(CXXFLAGS))
+ $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
+ 	$(call msg,CXX,,$@)
+-	$(Q)$(CXX) $(subst -D_GNU_SOURCE=,,$(CFLAGS)) $(filter %.a %.o %.cpp,$^) $(LDLIBS) -o $@
++	$(Q)$(CXX) $(CXXFLAGS) $(filter %.a %.o %.cpp,$^) $(LDLIBS) -o $@
+
+ # Benchmark runner
+ $(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(BPFOBJ)
+-- 
+2.47.1
+