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, 32 insertions, 0 deletions

diff --git a/arch/arm/mach-pxa/Makefile b/arch/arm/mach-pxa/Makefile
new file mode 100644
index 000000000..faccdd356
--- /dev/null
+++ b/arch/arm/mach-pxa/Makefile
@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux kernel.
+#
+
+# Common support (must be linked before board specific support)
+obj-y				+= devices.o generic.o irq.o reset.o
+obj-$(CONFIG_PM)		+= pm.o sleep.o standby.o
+
+# Generic drivers that other drivers may depend upon
+
+# SoC-specific code
+obj-$(CONFIG_PXA25x)		+= mfp-pxa2xx.o pxa2xx.o pxa25x.o
+obj-$(CONFIG_PXA27x)		+= mfp-pxa2xx.o pxa2xx.o pxa27x.o
+obj-$(CONFIG_PXA3xx)		+= mfp-pxa3xx.o pxa3xx.o smemc.o
+obj-$(CONFIG_CPU_PXA300)	+= pxa300.o
+obj-$(CONFIG_CPU_PXA320)	+= pxa320.o
+
+# NOTE: keep the order of boards in accordance to their order in Kconfig
+
+# Device Tree support
+obj-$(CONFIG_MACH_PXA25X_DT)	+= pxa-dt.o
+obj-$(CONFIG_MACH_PXA27X_DT)	+= pxa-dt.o
+obj-$(CONFIG_MACH_PXA3XX_DT)	+= pxa-dt.o
+
+# 3rd Party Dev Platforms
+obj-$(CONFIG_ARCH_GUMSTIX)	+= gumstix.o
+obj-$(CONFIG_GUMSTIX_AM200EPD)	+= am200epd.o
+obj-$(CONFIG_GUMSTIX_AM300EPD)	+= am300epd.o
+
+# End-user Products
+obj-$(CONFIG_PXA_SHARP_Cxx00)	+= spitz.o sharpsl_pm.o spitz_pm.o