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, 24 insertions, 0 deletions

diff --git a/arch/microblaze/lib/Makefile b/arch/microblaze/lib/Makefile
new file mode 100644
index 000000000..9fe7ab688
--- /dev/null
+++ b/arch/microblaze/lib/Makefile
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile
+#
+
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_ashldi3.o = -pg
+CFLAGS_REMOVE_ashrdi3.o = -pg
+CFLAGS_REMOVE_lshrdi3.o = -pg
+endif
+
+lib-y :=  memset.o
+
+ifeq ($(CONFIG_OPT_LIB_ASM),y)
+lib-y += fastcopy.o
+else
+lib-y += memcpy.o memmove.o
+endif
+
+lib-y += uaccess_old.o
+
+# libgcc-style stuff needed in the kernel
+obj-y += ashldi3.o ashrdi3.o cmpdi2.o divsi3.o lshrdi3.o modsi3.o
+obj-y += muldi3.o mulsi3.o ucmpdi2.o udivsi3.o umodsi3.o