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, 22 insertions, 0 deletions

diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile
new file mode 100644
index 000000000..245e67852
--- /dev/null
+++ b/fs/fuse/Makefile
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the FUSE filesystem.
+#
+
+# Needed for trace events
+ccflags-y = -I$(src)
+
+obj-$(CONFIG_FUSE_FS) += fuse.o
+obj-$(CONFIG_CUSE) += cuse.o
+obj-$(CONFIG_VIRTIO_FS) += virtiofs.o
+
+fuse-y := trace.o	# put trace.o first so we see ftrace errors sooner
+fuse-y += dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o ioctl.o req_timeout.o req.o
+fuse-y += poll.o notify.o
+fuse-y += iomode.o
+fuse-$(CONFIG_FUSE_DAX) += dax.o
+fuse-$(CONFIG_FUSE_PASSTHROUGH) += passthrough.o backing.o
+fuse-$(CONFIG_SYSCTL) += sysctl.o
+fuse-$(CONFIG_FUSE_IO_URING) += dev_uring.o
+
+virtiofs-y := virtio_fs.o