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 --- arch/powerpc/xmon/Makefile | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) create mode 100644 arch/powerpc/xmon/Makefile (limited to 'arch/powerpc/xmon/Makefile') diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile new file mode 100644 index 000000000..d74b14712 --- /dev/null +++ b/arch/powerpc/xmon/Makefile @@ -0,0 +1,19 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for xmon + +GCOV_PROFILE := n +KCOV_INSTRUMENT := n +UBSAN_SANITIZE := n +KASAN_SANITIZE := n +KCSAN_SANITIZE := n + +# Disable ftrace for the entire directory +ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE) + +# Clang stores addresses on the stack causing the frame size to blow +# out. See https://github.com/ClangBuiltLinux/linux/issues/252 +ccflags-$(CONFIG_CC_IS_CLANG) += -Wframe-larger-than=4096 + +obj-y += xmon.o nonstdio.o spr_access.o xmon_bpts.o + +obj-$(CONFIG_XMON_DISASSEMBLY) += ppc-dis.o ppc-opc.o -- cgit v1.3.1