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, 184 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/dib0090.h b/drivers/media/dvb-frontends/dib0090.h
new file mode 100644
index 000000000..e5cb31169
--- /dev/null
+++ b/drivers/media/dvb-frontends/dib0090.h
@@ -0,0 +1,184 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Linux-DVB Driver for DiBcom's DiB0090 base-band RF Tuner.
+ *
+ * Copyright (C) 2005-7 DiBcom (http://www.dibcom.fr/)
+ */
+#ifndef DIB0090_H
+#define DIB0090_H
+
+struct dvb_frontend;
+struct i2c_adapter;
+
+#define DEFAULT_DIB0090_I2C_ADDRESS 0x60
+
+struct dib0090_io_config {
+	u32 clock_khz;
+
+	u8 pll_bypass:1;
+	u8 pll_range:1;
+	u8 pll_prediv:6;
+	u8 pll_loopdiv:6;
+
+	u8 adc_clock_ratio;	/* valid is 8, 7 ,6 */
+	u16 pll_int_loop_filt;
+};
+
+struct dib0090_wbd_slope {
+	u16 max_freq;		/* for every frequency less than or equal to that field: this information is correct */
+	u16 slope_cold;
+	u16 offset_cold;
+	u16 slope_hot;
+	u16 offset_hot;
+	u8 wbd_gain;
+};
+
+struct dib0090_low_if_offset_table {
+	int std;
+	u32 RF_freq;
+	s32 offset_khz;
+};
+
+struct dib0090_config {
+	struct dib0090_io_config io;
+	int (*reset) (struct dvb_frontend *, int);
+	int (*sleep) (struct dvb_frontend *, int);
+
+	/*  offset in kHz */
+	int freq_offset_khz_uhf;
+	int freq_offset_khz_vhf;
+
+	int (*get_adc_power) (struct dvb_frontend *);
+
+	u8 clkouttobamse:1;	/* activate or deactivate clock output */
+	u8 analog_output;
+
+	u8 i2c_address;
+	/* add drives and other things if necessary */
+	u16 wbd_vhf_offset;
+	u16 wbd_cband_offset;
+	u8 use_pwm_agc;
+	u8 clkoutdrive;
+
+	u8 ls_cfg_pad_drv;
+	u8 data_tx_drv;
+
+	u8 in_soc;
+	const struct dib0090_low_if_offset_table *low_if;
+	u8 fref_clock_ratio;
+	u16 force_cband_input;
+	struct dib0090_wbd_slope *wbd;
+	u8 is_dib7090e;
+	u8 force_crystal_mode;
+};
+
+#if IS_REACHABLE(CONFIG_DVB_TUNER_DIB0090)
+extern struct dvb_frontend *dib0090_register(struct dvb_frontend *fe, struct i2c_adapter *i2c, const struct dib0090_config *config);
+extern struct dvb_frontend *dib0090_fw_register(struct dvb_frontend *fe, struct i2c_adapter *i2c, const struct dib0090_config *config);
+extern void dib0090_dcc_freq(struct dvb_frontend *fe, u8 fast);
+extern void dib0090_pwm_gain_reset(struct dvb_frontend *fe);
+extern u16 dib0090_get_wbd_target(struct dvb_frontend *tuner);
+extern u16 dib0090_get_wbd_offset(struct dvb_frontend *fe);
+extern int dib0090_gain_control(struct dvb_frontend *fe);
+extern enum frontend_tune_state dib0090_get_tune_state(struct dvb_frontend *fe);
+extern int dib0090_set_tune_state(struct dvb_frontend *fe, enum frontend_tune_state tune_state);
+extern void dib0090_get_current_gain(struct dvb_frontend *fe, u16 * rf, u16 * bb, u16 * rf_gain_limit, u16 * rflt);
+extern void dib0090_set_dc_servo(struct dvb_frontend *fe, u8 DC_servo_cutoff);
+extern int dib0090_set_switch(struct dvb_frontend *fe, u8 sw1, u8 sw2, u8 sw3);
+extern int dib0090_set_vga(struct dvb_frontend *fe, u8 onoff);
+extern int dib0090_update_rframp_7090(struct dvb_frontend *fe,
+		u8 cfg_sensitivity);
+extern int dib0090_update_tuning_table_7090(struct dvb_frontend *fe,
+		u8 cfg_sensitivity);
+#else
+static inline struct dvb_frontend *dib0090_register(struct dvb_frontend *fe, struct i2c_adapter *i2c, const struct dib0090_config *config)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return NULL;
+}
+
+static inline struct dvb_frontend *dib0090_fw_register(struct dvb_frontend *fe, struct i2c_adapter *i2c, struct dib0090_config *config)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return NULL;
+}
+
+static inline void dib0090_dcc_freq(struct dvb_frontend *fe, u8 fast)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+}
+
+static inline void dib0090_pwm_gain_reset(struct dvb_frontend *fe)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+}
+
+static inline u16 dib0090_get_wbd_target(struct dvb_frontend *tuner)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return 0;
+}
+
+static inline u16 dib0090_get_wbd_offset(struct dvb_frontend *fe)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return 0;
+}
+
+static inline int dib0090_gain_control(struct dvb_frontend *fe)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return -ENODEV;
+}
+
+static inline enum frontend_tune_state dib0090_get_tune_state(struct dvb_frontend *fe)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return CT_DONE;
+}
+
+static inline int dib0090_set_tune_state(struct dvb_frontend *fe, enum frontend_tune_state tune_state)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return -ENODEV;
+}
+
+static inline void dib0090_get_current_gain(struct dvb_frontend *fe, u16 * rf, u16 * bb, u16 * rf_gain_limit, u16 * rflt)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+}
+
+static inline void dib0090_set_dc_servo(struct dvb_frontend *fe, u8 DC_servo_cutoff)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+}
+
+static inline int dib0090_set_switch(struct dvb_frontend *fe,
+		u8 sw1, u8 sw2, u8 sw3)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return -ENODEV;
+}
+
+static inline int dib0090_set_vga(struct dvb_frontend *fe, u8 onoff)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return -ENODEV;
+}
+
+static inline int dib0090_update_rframp_7090(struct dvb_frontend *fe,
+		u8 cfg_sensitivity)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return -ENODEV;
+}
+
+static inline int dib0090_update_tuning_table_7090(struct dvb_frontend *fe,
+		u8 cfg_sensitivity)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return -ENODEV;
+}
+#endif
+
+#endif