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/x86/um/Makefile | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 arch/x86/um/Makefile (limited to 'arch/x86/um/Makefile') diff --git a/arch/x86/um/Makefile b/arch/x86/um/Makefile new file mode 100644 index 000000000..f9ea75bf4 --- /dev/null +++ b/arch/x86/um/Makefile @@ -0,0 +1,50 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) +# + +ifeq ($(CONFIG_X86_32),y) + BITS := 32 +else + BITS := 64 +endif + +obj-y = bugs_$(BITS).o delay.o fault.o \ + ptrace.o ptrace_$(BITS).o ptrace_user.o setjmp_$(BITS).o signal.o \ + stub_segv.o \ + sys_call_table_$(BITS).o sysrq_$(BITS).o tls_$(BITS).o \ + subarch.o os-Linux/ + +ifeq ($(CONFIG_X86_32),y) + +obj-y += syscalls_32.o + +subarch-y = ../lib/string_32.o ../lib/atomic64_32.o ../lib/atomic64_cx8_32.o +subarch-y += ../lib/cmpxchg8b_emu.o ../lib/atomic64_386_32.o +subarch-y += ../lib/checksum_32.o +subarch-y += ../kernel/sys_ia32.o + +else + +obj-y += mem_64.o syscalls_64.o vdso/ + +subarch-y = ../lib/csum-partial_64.o ../lib/memcpy_64.o \ + ../lib/memmove_64.o ../lib/memset_64.o + +endif + +subarch-$(CONFIG_MODULES) += ../kernel/module.o + +USER_OBJS := bugs_$(BITS).o ptrace_user.o fault.o + +$(obj)/user-offsets.s: c_flags = -Wp,-MD,$(depfile) $(USER_CFLAGS) \ + -Iarch/x86/include/generated +targets += user-offsets.s + +include/generated/user_constants.h: $(obj)/user-offsets.s FORCE + $(call filechk,offsets,__USER_CONSTANT_H__) + +UNPROFILE_OBJS := stub_segv.o +CFLAGS_stub_segv.o := $(CFLAGS_NO_HARDENING) + +include $(srctree)/arch/um/scripts/Makefile.rules -- cgit v1.3.1