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, 136 insertions, 0 deletions

diff --git a/include/trace/events/spmi.h b/include/trace/events/spmi.h
new file mode 100644
index 000000000..a6819fd85
--- /dev/null
+++ b/include/trace/events/spmi.h
@@ -0,0 +1,136 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM spmi
+
+#if !defined(_TRACE_SPMI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SPMI_H
+
+#include <linux/spmi.h>
+#include <linux/tracepoint.h>
+
+/*
+ * drivers/spmi/spmi.c
+ */
+
+TRACE_EVENT(spmi_write_begin,
+	TP_PROTO(u8 opcode, u8 sid, u16 addr, u8 len, const u8 *buf),
+	TP_ARGS(opcode, sid, addr, len, buf),
+
+	TP_STRUCT__entry(
+		__field		( u8,         opcode    )
+		__field		( u8,         sid       )
+		__field		( u16,        addr      )
+		__field		( u8,         len       )
+		__dynamic_array	( u8,   buf,  len       )
+	),
+
+	TP_fast_assign(
+		__entry->opcode = opcode;
+		__entry->sid    = sid;
+		__entry->addr   = addr;
+		__entry->len    = len;
+		memcpy(__get_dynamic_array(buf), buf, len);
+	),
+
+	TP_printk("opc=%d sid=%02d addr=0x%04x len=%d buf=0x[%*phD]",
+		  (int)__entry->opcode, (int)__entry->sid,
+		  (int)__entry->addr, (int)__entry->len,
+		  (int)__entry->len, __get_dynamic_array(buf))
+);
+
+TRACE_EVENT(spmi_write_end,
+	TP_PROTO(u8 opcode, u8 sid, u16 addr, int ret),
+	TP_ARGS(opcode, sid, addr, ret),
+
+	TP_STRUCT__entry(
+		__field		( u8,         opcode    )
+		__field		( u8,         sid       )
+		__field		( u16,        addr      )
+		__field		( int,        ret       )
+	),
+
+	TP_fast_assign(
+		__entry->opcode = opcode;
+		__entry->sid    = sid;
+		__entry->addr   = addr;
+		__entry->ret    = ret;
+	),
+
+	TP_printk("opc=%d sid=%02d addr=0x%04x ret=%d",
+		  (int)__entry->opcode, (int)__entry->sid,
+		  (int)__entry->addr, __entry->ret)
+);
+
+TRACE_EVENT(spmi_read_begin,
+	TP_PROTO(u8 opcode, u8 sid, u16 addr),
+	TP_ARGS(opcode, sid, addr),
+
+	TP_STRUCT__entry(
+		__field		( u8,         opcode    )
+		__field		( u8,         sid       )
+		__field		( u16,        addr      )
+	),
+
+	TP_fast_assign(
+		__entry->opcode = opcode;
+		__entry->sid    = sid;
+		__entry->addr   = addr;
+	),
+
+	TP_printk("opc=%d sid=%02d addr=0x%04x",
+		  (int)__entry->opcode, (int)__entry->sid,
+		  (int)__entry->addr)
+);
+
+TRACE_EVENT(spmi_read_end,
+	TP_PROTO(u8 opcode, u8 sid, u16 addr, int ret, u8 len, const u8 *buf),
+	TP_ARGS(opcode, sid, addr, ret, len, buf),
+
+	TP_STRUCT__entry(
+		__field		( u8,         opcode    )
+		__field		( u8,         sid       )
+		__field		( u16,        addr      )
+		__field		( int,        ret       )
+		__field		( u8,         len       )
+		__dynamic_array	( u8,   buf,  len       )
+	),
+
+	TP_fast_assign(
+		__entry->opcode = opcode;
+		__entry->sid    = sid;
+		__entry->addr   = addr;
+		__entry->ret    = ret;
+		__entry->len    = len;
+		memcpy(__get_dynamic_array(buf), buf, len);
+	),
+
+	TP_printk("opc=%d sid=%02d addr=0x%04x ret=%d len=%02d buf=0x[%*phD]",
+		  (int)__entry->opcode, (int)__entry->sid,
+		  (int)__entry->addr, __entry->ret, (int)__entry->len,
+		  (int)__entry->len, __get_dynamic_array(buf))
+);
+
+TRACE_EVENT(spmi_cmd,
+	TP_PROTO(u8 opcode, u8 sid, int ret),
+	TP_ARGS(opcode, sid, ret),
+
+	TP_STRUCT__entry(
+		__field		( u8,         opcode    )
+		__field		( u8,         sid       )
+		__field		( int,        ret       )
+	),
+
+	TP_fast_assign(
+		__entry->opcode = opcode;
+		__entry->sid    = sid;
+		__entry->ret    = ret;
+	),
+
+	TP_printk("opc=%d sid=%02d ret=%d", (int)__entry->opcode,
+		  (int)__entry->sid, ret)
+);
+
+#endif /* _TRACE_SPMI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>