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, 44 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/si2165.h b/drivers/media/dvb-frontends/si2165.h
new file mode 100644
index 000000000..adc5e1875
--- /dev/null
+++ b/drivers/media/dvb-frontends/si2165.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Driver for Silicon Labs SI2165 DVB-C/-T Demodulator
+ *
+ * Copyright (C) 2013-2017 Matthias Schwarzott <zzam@gentoo.org>
+ *
+ * References:
+ *   https://www.silabs.com/Support%20Documents/TechnicalDocs/Si2165-short.pdf
+ */
+
+#ifndef _DVB_SI2165_H
+#define _DVB_SI2165_H
+
+#include <linux/dvb/frontend.h>
+
+enum {
+	SI2165_MODE_OFF = 0x00,
+	SI2165_MODE_PLL_EXT = 0x20,
+	SI2165_MODE_PLL_XTAL = 0x21
+};
+
+/* I2C addresses
+ * possible values: 0x64,0x65,0x66,0x67
+ */
+struct si2165_platform_data {
+	/*
+	 * frontend
+	 * returned by driver
+	 */
+	struct dvb_frontend **fe;
+
+	/* external clock or XTAL */
+	u8 chip_mode;
+
+	/* frequency of external clock or xtal in Hz
+	 * possible values: 4000000, 16000000, 20000000, 240000000, 27000000
+	 */
+	u32 ref_freq_hz;
+
+	/* invert the spectrum */
+	bool inversion;
+};
+
+#endif /* _DVB_SI2165_H */