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, 73 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/gp8psk-fe.h b/drivers/media/dvb-frontends/gp8psk-fe.h
new file mode 100644
index 000000000..2805a3b67
--- /dev/null
+++ b/drivers/media/dvb-frontends/gp8psk-fe.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * gp8psk_fe driver
+ */
+
+#ifndef GP8PSK_FE_H
+#define GP8PSK_FE_H
+
+#include <linux/types.h>
+
+/* gp8psk commands */
+
+#define GET_8PSK_CONFIG                 0x80    /* in */
+#define SET_8PSK_CONFIG                 0x81
+#define I2C_WRITE			0x83
+#define I2C_READ			0x84
+#define ARM_TRANSFER                    0x85
+#define TUNE_8PSK                       0x86
+#define GET_SIGNAL_STRENGTH             0x87    /* in */
+#define LOAD_BCM4500                    0x88
+#define BOOT_8PSK                       0x89    /* in */
+#define START_INTERSIL                  0x8A    /* in */
+#define SET_LNB_VOLTAGE                 0x8B
+#define SET_22KHZ_TONE                  0x8C
+#define SEND_DISEQC_COMMAND             0x8D
+#define SET_DVB_MODE                    0x8E
+#define SET_DN_SWITCH                   0x8F
+#define GET_SIGNAL_LOCK                 0x90    /* in */
+#define GET_FW_VERS			0x92
+#define GET_SERIAL_NUMBER               0x93    /* in */
+#define USE_EXTRA_VOLT                  0x94
+#define GET_FPGA_VERS			0x95
+#define CW3K_INIT			0x9d
+
+/* PSK_configuration bits */
+#define bm8pskStarted                   0x01
+#define bm8pskFW_Loaded                 0x02
+#define bmIntersilOn                    0x04
+#define bmDVBmode                       0x08
+#define bm22kHz                         0x10
+#define bmSEL18V                        0x20
+#define bmDCtuned                       0x40
+#define bmArmed                         0x80
+
+/* Satellite modulation modes */
+#define ADV_MOD_DVB_QPSK 0     /* DVB-S QPSK */
+#define ADV_MOD_TURBO_QPSK 1   /* Turbo QPSK */
+#define ADV_MOD_TURBO_8PSK 2   /* Turbo 8PSK (also used for Trellis 8PSK) */
+#define ADV_MOD_TURBO_16QAM 3  /* Turbo 16QAM (also used for Trellis 8PSK) */
+
+#define ADV_MOD_DCII_C_QPSK 4  /* Digicipher II Combo */
+#define ADV_MOD_DCII_I_QPSK 5  /* Digicipher II I-stream */
+#define ADV_MOD_DCII_Q_QPSK 6  /* Digicipher II Q-stream */
+#define ADV_MOD_DCII_C_OQPSK 7 /* Digicipher II offset QPSK */
+#define ADV_MOD_DSS_QPSK 8     /* DSS (DIRECTV) QPSK */
+#define ADV_MOD_DVB_BPSK 9     /* DVB-S BPSK */
+
+/* firmware revision id's */
+#define GP8PSK_FW_REV1			0x020604
+#define GP8PSK_FW_REV2			0x020704
+#define GP8PSK_FW_VERS(_fw_vers) \
+	((_fw_vers)[2]<<0x10 | (_fw_vers)[1]<<0x08 | (_fw_vers)[0])
+
+struct gp8psk_fe_ops {
+	int (*in)(void *priv, u8 req, u16 value, u16 index, u8 *b, int blen);
+	int (*out)(void *priv, u8 req, u16 value, u16 index, u8 *b, int blen);
+	int (*reload)(void *priv);
+};
+
+struct dvb_frontend *gp8psk_fe_attach(const struct gp8psk_fe_ops *ops,
+				      void *priv, bool is_rev1);
+
+#endif