From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- scripts/Makefile.clang | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 scripts/Makefile.clang (limited to 'scripts/Makefile.clang') diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang new file mode 100644 index 000000000..b67636b28 --- /dev/null +++ b/scripts/Makefile.clang @@ -0,0 +1,42 @@ +# Individual arch/{arch}/Makefiles should use -EL/-EB to set intended +# endianness and -m32/-m64 to set word size based on Kconfigs instead of +# relying on the target triple. +CLANG_TARGET_FLAGS_arm := arm-linux-gnueabi +CLANG_TARGET_FLAGS_arm64 := aarch64-linux-gnu +CLANG_TARGET_FLAGS_hexagon := hexagon-linux-musl +CLANG_TARGET_FLAGS_loongarch := loongarch64-linux-gnusf +CLANG_TARGET_FLAGS_m68k := m68k-linux-gnu +CLANG_TARGET_FLAGS_mips := mipsel-linux-gnu +CLANG_TARGET_FLAGS_powerpc := powerpc64le-linux-gnu +CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu +CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu +CLANG_TARGET_FLAGS_sparc := sparc64-linux-gnu +CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu +# This is only for i386 UM builds, which need the 32-bit target not -m32 +CLANG_TARGET_FLAGS_i386 := i386-linux-gnu +CLANG_TARGET_FLAGS_um := $(CLANG_TARGET_FLAGS_$(SUBARCH)) +CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(SRCARCH)) + +ifeq ($(CLANG_TARGET_FLAGS),) +$(error add '--target=' option to scripts/Makefile.clang) +else +CLANG_FLAGS += --target=$(CLANG_TARGET_FLAGS) +endif + +ifeq ($(LLVM_IAS),0) +CLANG_FLAGS += -fno-integrated-as +GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit)) +CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) +else +CLANG_FLAGS += -fintegrated-as +endif +# By default, clang only warns when it encounters an unknown warning flag or +# certain optimization flags it knows it has not implemented. +# Make it behave more like gcc by erroring when these flags are encountered +# so they can be implemented or wrapped in cc-option. +CLANG_FLAGS += -Werror=unknown-warning-option +CLANG_FLAGS += -Werror=ignored-optimization-argument +CLANG_FLAGS += -Werror=option-ignored +CLANG_FLAGS += -Werror=unused-command-line-argument +KBUILD_CPPFLAGS += $(CLANG_FLAGS) +export CLANG_FLAGS -- cgit v1.3.1