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, 10 insertions, 0 deletions

diff --git a/arch/mips/dec/Makefile b/arch/mips/dec/Makefile
new file mode 100644
index 000000000..c9f62f1da
--- /dev/null
+++ b/arch/mips/dec/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the DECstation family specific parts of the kernel
+#
+
+obj-y		:= ecc-berr.o int-handler.o ioasic-irq.o kn01-berr.o \
+		   kn02-irq.o kn02xa-berr.o platform.o reset.o setup.o time.o
+
+obj-$(CONFIG_TC)		+= tc.o
+obj-$(CONFIG_CPU_HAS_WB)	+= wbflush.o