selftests/bpf: Reject graph kptr use after RCU unlockgrafted

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 <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
new file mode 100644
index 000000000..59612d2f2
--- /dev/null
+++ b/arch/arm64/kvm/Makefile
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for Kernel-based Virtual Machine module
+#
+
+ccflags-y += -I $(src)
+
+include $(srctree)/virt/kvm/Makefile.kvm
+
+obj-$(CONFIG_KVM) += kvm.o
+obj-$(CONFIG_KVM) += hyp/
+
+CFLAGS_sys_regs.o += -Wno-override-init
+CFLAGS_handle_exit.o += -Wno-override-init
+
+kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
+	 inject_fault.o va_layout.o handle_exit.o config.o \
+	 guest.o debug.o reset.o sys_regs.o stacktrace.o \
+	 vgic-sys-reg-v3.o fpsimd.o pkvm.o \
+	 arch_timer.o trng.o vmid.o emulate-nested.o nested.o at.o \
+	 vgic/vgic.o vgic/vgic-init.o \
+	 vgic/vgic-irqfd.o vgic/vgic-v2.o \
+	 vgic/vgic-v3.o vgic/vgic-v4.o \
+	 vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
+	 vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
+	 vgic/vgic-its.o vgic/vgic-debug.o vgic/vgic-v3-nested.o \
+	 vgic/vgic-v5.o
+
+kvm-$(CONFIG_HW_PERF_EVENTS)  += pmu-emul.o pmu.o
+kvm-$(CONFIG_ARM64_PTR_AUTH)  += pauth.o
+kvm-$(CONFIG_PTDUMP_STAGE2_DEBUGFS) += ptdump.o
+
+kvm-$(CONFIG_NVHE_EL2_TRACING) += hyp_trace.o
+
+always-y := hyp_constants.h hyp-constants.s
+
+define rule_gen_hyp_constants
+	$(call filechk,offsets,__HYP_CONSTANTS_H__)
+endef
+
+CFLAGS_hyp-constants.o = -I $(src)/hyp/include
+$(obj)/hyp-constants.s: $(src)/hyp/hyp-constants.c FORCE
+	$(call if_changed_dep,cc_s_c)
+
+$(obj)/hyp_constants.h: $(obj)/hyp-constants.s FORCE
+	$(call if_changed_rule,gen_hyp_constants)
+
+obj-kvm := $(addprefix $(obj)/, $(kvm-y))
+$(obj-kvm): $(obj)/hyp_constants.h