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, 42 insertions, 0 deletions

diff --git a/sound/soc/meson/gx-interface.h b/sound/soc/meson/gx-interface.h
new file mode 100644
index 000000000..2a6207e39
--- /dev/null
+++ b/sound/soc/meson/gx-interface.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+/*
+ * Copyright (c) 2026 Baylibre SAS.
+ * Author: Valerio Setti <vsetti@baylibre.com>
+ */
+
+#ifndef _MESON_GX_INTERFACE_H
+#define _MESON_GX_INTERFACE_H
+
+#include <linux/clk.h>
+#include <linux/regmap.h>
+#include <sound/pcm.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+
+struct gx_iface {
+	struct clk *mclk;
+	unsigned long mclk_rate;
+
+	/* format is common to all the DAIs of the iface */
+	unsigned int fmt;
+};
+
+struct gx_stream {
+	struct gx_iface *iface;
+	struct list_head formatter_list;
+	struct mutex lock;
+	unsigned int channels;
+	unsigned int width;
+	unsigned int physical_width;
+	bool ready;
+
+	/* For continuous clock tracking */
+	bool clk_enabled;
+};
+
+struct gx_stream *gx_stream_alloc(struct gx_iface *iface);
+void gx_stream_free(struct gx_stream *ts);
+int gx_stream_start(struct gx_stream *ts);
+void gx_stream_stop(struct gx_stream *ts);
+
+#endif /* _MESON_GX_INTERFACE_H */