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, 72 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-client-probes.h b/sound/soc/sof/sof-client-probes.h
new file mode 100644
index 000000000..47d0582b8
--- /dev/null
+++ b/sound/soc/sof/sof-client-probes.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __SOF_CLIENT_PROBES_H
+#define __SOF_CLIENT_PROBES_H
+
+struct snd_compr_stream;
+struct snd_compr_tstamp64;
+struct snd_compr_params;
+struct sof_client_dev;
+struct snd_soc_dai;
+
+/*
+ * Callbacks used on platforms where the control for audio is split between
+ * DSP and host, like HDA.
+ */
+struct sof_probes_host_ops {
+	int (*startup)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+		       struct snd_soc_dai *dai, u32 *stream_id);
+	int (*shutdown)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+			struct snd_soc_dai *dai);
+	int (*set_params)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+			  struct snd_compr_params *params,
+			  struct snd_soc_dai *dai);
+	int (*trigger)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+		       int cmd, struct snd_soc_dai *dai);
+	int (*pointer)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+		       struct snd_compr_tstamp64 *tstamp,
+		       struct snd_soc_dai *dai);
+};
+
+struct sof_probe_point_desc {
+	unsigned int buffer_id;
+	unsigned int purpose;
+	unsigned int stream_tag;
+} __packed;
+
+enum sof_probe_info_type {
+	PROBES_INFO_ACTIVE_PROBES,
+	PROBES_INFO_AVAILABE_PROBES,
+};
+
+struct sof_probes_ipc_ops {
+	int (*init)(struct sof_client_dev *cdev, u32 stream_tag,
+		    size_t buffer_size);
+	int (*deinit)(struct sof_client_dev *cdev);
+	int (*points_info)(struct sof_client_dev *cdev,
+			   struct sof_probe_point_desc **desc,
+			   size_t *num_desc, enum sof_probe_info_type type);
+	int (*point_print)(struct sof_client_dev *cdev, char *buf, size_t size,
+			   struct sof_probe_point_desc *desc);
+	int (*points_add)(struct sof_client_dev *cdev,
+			  struct sof_probe_point_desc *desc,
+			  size_t num_desc);
+	int (*points_remove)(struct sof_client_dev *cdev,
+			     unsigned int *buffer_id, size_t num_buffer_id);
+};
+
+extern const struct sof_probes_ipc_ops ipc3_probe_ops;
+extern const struct sof_probes_ipc_ops ipc4_probe_ops;
+
+struct sof_probes_priv {
+	struct dentry *dfs_points;
+	struct dentry *dfs_points_remove;
+	u32 extractor_stream_tag;
+	struct snd_soc_card card;
+	void *ipc_priv;
+
+	const struct sof_probes_host_ops *host_ops;
+	const struct sof_probes_ipc_ops *ipc_ops;
+};
+
+#endif