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, 38 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/rtl2830.h b/drivers/media/dvb-frontends/rtl2830.h
new file mode 100644
index 000000000..fb5522025
--- /dev/null
+++ b/drivers/media/dvb-frontends/rtl2830.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Realtek RTL2830 DVB-T demodulator driver
+ *
+ * Copyright (C) 2011 Antti Palosaari <crope@iki.fi>
+ */
+
+#ifndef RTL2830_H
+#define RTL2830_H
+
+#include <linux/dvb/frontend.h>
+
+/**
+ * struct rtl2830_platform_data - Platform data for the rtl2830 driver
+ * @clk: Clock frequency (4000000, 16000000, 25000000, 28800000).
+ * @spec_inv: Spectrum inversion.
+ * @vtop: AGC take-over point.
+ * @krf: AGC ratio.
+ * @agc_targ_val: AGC.
+ * @get_dvb_frontend: Get DVB frontend.
+ * @get_i2c_adapter: Get I2C adapter.
+ * @pid_filter: Set PID to PID filter.
+ * @pid_filter_ctrl: Control PID filter.
+ */
+struct rtl2830_platform_data {
+	u32 clk;
+	bool spec_inv;
+	u8 vtop;
+	u8 krf;
+	u8 agc_targ_val;
+
+	struct dvb_frontend* (*get_dvb_frontend)(struct i2c_client *);
+	struct i2c_adapter* (*get_i2c_adapter)(struct i2c_client *);
+	int (*pid_filter)(struct dvb_frontend *, u8, u16, int);
+	int (*pid_filter_ctrl)(struct dvb_frontend *, int);
+};
+
+#endif /* RTL2830_H */