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, 65 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/dvb-pll.h b/drivers/media/dvb-frontends/dvb-pll.h
new file mode 100644
index 000000000..718388887
--- /dev/null
+++ b/drivers/media/dvb-frontends/dvb-pll.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * descriptions + helper functions for simple dvb plls.
+ */
+
+#ifndef __DVB_PLL_H__
+#define __DVB_PLL_H__
+
+#include <linux/i2c.h>
+#include <media/dvb_frontend.h>
+
+#define DVB_PLL_UNDEFINED               0
+#define DVB_PLL_THOMSON_DTT7579         1
+#define DVB_PLL_THOMSON_DTT759X         2
+#define DVB_PLL_LG_Z201                 3
+#define DVB_PLL_UNKNOWN_1               4
+#define DVB_PLL_TUA6010XS               5
+#define DVB_PLL_ENV57H1XD5              6
+#define DVB_PLL_TUA6034                 7
+#define DVB_PLL_TDA665X                 8
+#define DVB_PLL_TDED4                   9
+#define DVB_PLL_TDHU2                  10
+#define DVB_PLL_SAMSUNG_TBMV           11
+#define DVB_PLL_PHILIPS_SD1878_TDA8261 12
+#define DVB_PLL_OPERA1                 13
+#define DVB_PLL_SAMSUNG_DTOS403IH102A  14
+#define DVB_PLL_SAMSUNG_TDTC9251DH0    15
+#define DVB_PLL_SAMSUNG_TBDU18132      16
+#define DVB_PLL_SAMSUNG_TBMU24112      17
+#define DVB_PLL_TDEE4		       18
+#define DVB_PLL_THOMSON_DTT7520X       19
+#define DVB_PLL_TUA6034_FRIIO          20
+#define DVB_PLL_TDA665X_EARTH_PT1      21
+
+struct dvb_pll_config {
+	struct dvb_frontend *fe;
+};
+
+#if IS_REACHABLE(CONFIG_DVB_PLL)
+/**
+ * dvb_pll_attach - Attach a dvb-pll to the supplied frontend structure.
+ *
+ * @fe: Frontend to attach to.
+ * @pll_addr: i2c address of the PLL (if used).
+ * @i2c: i2c adapter to use (set to NULL if not used).
+ * @pll_desc_id: dvb_pll_desc to use.
+ *
+ * return: Frontend pointer on success, NULL on failure
+ */
+extern struct dvb_frontend *dvb_pll_attach(struct dvb_frontend *fe,
+					   int pll_addr,
+					   struct i2c_adapter *i2c,
+					   unsigned int pll_desc_id);
+#else
+static inline struct dvb_frontend *dvb_pll_attach(struct dvb_frontend *fe,
+					   int pll_addr,
+					   struct i2c_adapter *i2c,
+					   unsigned int pll_desc_id)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return NULL;
+}
+#endif
+
+#endif