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/drivers/media/dvb-frontends/cxd2099.h b/drivers/media/dvb-frontends/cxd2099.h
new file mode 100644
index 000000000..5d4060007
--- /dev/null
+++ b/drivers/media/dvb-frontends/cxd2099.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * cxd2099.h: Driver for the Sony CXD2099AR Common Interface Controller
+ *
+ * Copyright (C) 2010-2011 Digital Devices GmbH
+ */
+
+#ifndef _CXD2099_H_
+#define _CXD2099_H_
+
+#include <media/dvb_ca_en50221.h>
+
+struct cxd2099_cfg {
+	u32 bitrate;
+	u8  polarity;
+	u8  clock_mode;
+
+	u32 max_i2c;
+
+	/* ptr to DVB CA struct */
+	struct dvb_ca_en50221 **en;
+};
+
+#endif