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, 101 insertions, 0 deletions

diff --git a/drivers/media/i2c/max2175.h b/drivers/media/i2c/max2175.h
new file mode 100644
index 000000000..4c722ea3e
--- /dev/null
+++ b/drivers/media/i2c/max2175.h
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Maxim Integrated MAX2175 RF to Bits tuner driver
+ *
+ * This driver & most of the hard coded values are based on the reference
+ * application delivered by Maxim for this device.
+ *
+ * Copyright (C) 2016 Maxim Integrated Products
+ * Copyright (C) 2017 Renesas Electronics Corporation
+ */
+
+#ifndef __MAX2175_H__
+#define __MAX2175_H__
+
+#define MAX2175_EU_XTAL_FREQ	36864000	/* In Hz */
+#define MAX2175_NA_XTAL_FREQ	40186125	/* In Hz */
+
+enum max2175_region {
+	MAX2175_REGION_EU = 0,	/* Europe */
+	MAX2175_REGION_NA,	/* North America */
+};
+
+enum max2175_band {
+	MAX2175_BAND_AM = 0,
+	MAX2175_BAND_FM,
+	MAX2175_BAND_VHF,
+	MAX2175_BAND_L,
+};
+
+enum max2175_eu_mode {
+	/* EU modes */
+	MAX2175_EU_FM_1_2 = 0,
+	MAX2175_DAB_1_2,
+
+	/*
+	 * Other possible modes to add in future
+	 * MAX2175_DAB_1_0,
+	 * MAX2175_DAB_1_3,
+	 * MAX2175_EU_FM_2_2,
+	 * MAX2175_EU_FMHD_4_0,
+	 * MAX2175_EU_AM_1_0,
+	 * MAX2175_EU_AM_2_2,
+	 */
+};
+
+enum max2175_na_mode {
+	/* NA modes */
+	MAX2175_NA_FM_1_0 = 0,
+	MAX2175_NA_FM_2_0,
+
+	/*
+	 * Other possible modes to add in future
+	 * MAX2175_NA_FMHD_1_0,
+	 * MAX2175_NA_FMHD_1_2,
+	 * MAX2175_NA_AM_1_0,
+	 * MAX2175_NA_AM_1_2,
+	 */
+};
+
+/* Supported I2S modes */
+enum {
+	MAX2175_I2S_MODE0 = 0,
+	MAX2175_I2S_MODE1,
+	MAX2175_I2S_MODE2,
+	MAX2175_I2S_MODE3,
+	MAX2175_I2S_MODE4,
+};
+
+/* Coefficient table groups */
+enum {
+	MAX2175_CH_MSEL = 0,
+	MAX2175_EQ_MSEL,
+	MAX2175_AA_MSEL,
+};
+
+/* HSLS LO injection polarity */
+enum {
+	MAX2175_LO_BELOW_DESIRED = 0,
+	MAX2175_LO_ABOVE_DESIRED,
+};
+
+/* Channel FSM modes */
+enum max2175_csm_mode {
+	MAX2175_LOAD_TO_BUFFER = 0,
+	MAX2175_PRESET_TUNE,
+	MAX2175_SEARCH,
+	MAX2175_AF_UPDATE,
+	MAX2175_JUMP_FAST_TUNE,
+	MAX2175_CHECK,
+	MAX2175_LOAD_AND_SWAP,
+	MAX2175_END,
+	MAX2175_BUFFER_PLUS_PRESET_TUNE,
+	MAX2175_BUFFER_PLUS_SEARCH,
+	MAX2175_BUFFER_PLUS_AF_UPDATE,
+	MAX2175_BUFFER_PLUS_JUMP_FAST_TUNE,
+	MAX2175_BUFFER_PLUS_CHECK,
+	MAX2175_BUFFER_PLUS_LOAD_AND_SWAP,
+	MAX2175_NO_ACTION
+};
+
+#endif /* __MAX2175_H__ */