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, 26 insertions, 0 deletions

diff --git a/scripts/modules-check.sh b/scripts/modules-check.sh
new file mode 100755
index 000000000..4c8da90de
--- /dev/null
+++ b/scripts/modules-check.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+if [ $# != 1 ]; then
+	echo "Usage: $0 <modules.order>" >& 2
+	exit 1
+fi
+
+exit_code=0
+
+# Check uniqueness of module names
+check_same_name_modules()
+{
+	for m in $(sed 's:.*/::' "$1" | sort | uniq -d)
+	do
+		echo "error: the following would cause module name conflict:" >&2
+		sed -n "/\/$m/s:^\(.*\)\.o\$:  \1.ko:p" "$1" >&2
+		exit_code=1
+	done
+}
+
+check_same_name_modules "$1"
+
+exit $exit_code