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, 25 insertions, 0 deletions

diff --git a/arch/x86/pci/Makefile b/arch/x86/pci/Makefile
new file mode 100644
index 000000000..c1efd5b0d
--- /dev/null
+++ b/arch/x86/pci/Makefile
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y				:= i386.o init.o
+
+obj-$(CONFIG_PCI_BIOS)		+= pcbios.o
+obj-$(CONFIG_PCI_MMCONFIG)	+= mmconfig_$(BITS).o direct.o mmconfig-shared.o
+obj-$(CONFIG_PCI_DIRECT)	+= direct.o
+obj-$(CONFIG_PCI_OLPC)		+= olpc.o
+obj-$(CONFIG_PCI_XEN)		+= xen.o
+
+obj-y				+= fixup.o
+obj-$(CONFIG_ACPI)		+= acpi.o
+obj-y				+= legacy.o irq.o
+
+obj-$(CONFIG_X86_INTEL_CE)	+= ce4100.o
+obj-$(CONFIG_X86_INTEL_MID)	+= intel_mid.o
+
+obj-$(CONFIG_X86_NUMACHIP)	+= numachip.o
+
+obj-y				+= common.o early.o
+obj-y				+= bus_numa.o
+
+obj-$(CONFIG_AMD_NB)		+= amd_bus.o
+obj-$(CONFIG_PCI_CNB20LE_QUIRK)	+= broadcom_bus.o
+
+ccflags-$(CONFIG_PCI_DEBUG)	+= -DDEBUG