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, 21 insertions, 0 deletions

diff --git a/drivers/ata/sata_gemini.h b/drivers/ata/sata_gemini.h
new file mode 100644
index 000000000..b6e4a5c86
--- /dev/null
+++ b/drivers/ata/sata_gemini.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Header for the Gemini SATA bridge */
+#ifndef SATA_GEMINI_H
+#define SATA_GEMINI_H
+
+struct sata_gemini;
+
+enum gemini_muxmode {
+	GEMINI_MUXMODE_0 = 0,
+	GEMINI_MUXMODE_1,
+	GEMINI_MUXMODE_2,
+	GEMINI_MUXMODE_3,
+};
+
+struct sata_gemini *gemini_sata_bridge_get(void);
+bool gemini_sata_bridge_enabled(struct sata_gemini *sg, bool is_ata1);
+enum gemini_muxmode gemini_sata_get_muxmode(struct sata_gemini *sg);
+int gemini_sata_start_bridge(struct sata_gemini *sg, unsigned int bridge);
+void gemini_sata_stop_bridge(struct sata_gemini *sg, unsigned int bridge);
+
+#endif