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, 13 insertions, 0 deletions

diff --git a/scripts/xen-hypercalls.sh b/scripts/xen-hypercalls.sh
new file mode 100755
index 000000000..f18b00843
--- /dev/null
+++ b/scripts/xen-hypercalls.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+out="$1"
+shift
+in="$@"
+
+for i in $in; do
+	eval $CPP $LINUXINCLUDE -dD -imacros "$i" -x c /dev/null
+done | \
+awk '$1 == "#define" && $2 ~ /__HYPERVISOR_[a-z][a-z_0-9]*/ { v[$3] = $2 }
+	END {   print "/* auto-generated by scripts/xen-hypercall.sh */"
+		for (i in v) if (!(v[i] in v))
+			print "HYPERCALL("substr(v[i], 14)")"}' | sort -u >$out