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, 46 insertions, 0 deletions

diff --git a/fs/afs/Makefile b/fs/afs/Makefile
new file mode 100644
index 000000000..0d8f1982d
--- /dev/null
+++ b/fs/afs/Makefile
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for Red Hat Linux AFS client.
+#
+
+kafs-y := \
+	addr_list.o \
+	addr_prefs.o \
+	callback.o \
+	cell.o \
+	cm_security.o \
+	cmservice.o \
+	dir.o \
+	dir_edit.o \
+	dir_search.o \
+	dir_silly.o \
+	dynroot.o \
+	file.o \
+	flock.o \
+	fsclient.o \
+	fs_operation.o \
+	fs_probe.o \
+	inode.o \
+	main.o \
+	misc.o \
+	mntpt.o \
+	rotate.o \
+	rxrpc.o \
+	security.o \
+	server.o \
+	server_list.o \
+	super.o \
+	symlink.o \
+	validation.o \
+	vlclient.o \
+	vl_alias.o \
+	vl_list.o \
+	vl_probe.o \
+	vl_rotate.o \
+	volume.o \
+	write.o \
+	xattr.o \
+	yfsclient.o
+
+kafs-$(CONFIG_PROC_FS) += proc.o
+obj-$(CONFIG_AFS_FS)  := kafs.o