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, 89 insertions, 0 deletions

diff --git a/sound/soc/codecs/lpass-macro-common.c b/sound/soc/codecs/lpass-macro-common.c
new file mode 100644
index 000000000..7e59616ed
--- /dev/null
+++ b/sound/soc/codecs/lpass-macro-common.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2022, The Linux Foundation. All rights reserved.
+
+#include <linux/cleanup.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
+
+#include "lpass-macro-common.h"
+
+static DEFINE_MUTEX(lpass_codec_mutex);
+static enum lpass_codec_version lpass_codec_version;
+
+struct lpass_macro *lpass_macro_pds_init(struct device *dev)
+{
+	struct lpass_macro *l_pds;
+	int ret;
+
+	if (!of_property_present(dev->of_node, "power-domains"))
+		return NULL;
+
+	l_pds = devm_kzalloc(dev, sizeof(*l_pds), GFP_KERNEL);
+	if (!l_pds)
+		return ERR_PTR(-ENOMEM);
+
+	l_pds->macro_pd = dev_pm_domain_attach_by_name(dev, "macro");
+	if (IS_ERR_OR_NULL(l_pds->macro_pd)) {
+		ret = l_pds->macro_pd ? PTR_ERR(l_pds->macro_pd) : -ENODATA;
+		goto macro_err;
+	}
+
+	ret = pm_runtime_resume_and_get(l_pds->macro_pd);
+	if (ret < 0)
+		goto macro_sync_err;
+
+	l_pds->dcodec_pd = dev_pm_domain_attach_by_name(dev, "dcodec");
+	if (IS_ERR_OR_NULL(l_pds->dcodec_pd)) {
+		ret = l_pds->dcodec_pd ? PTR_ERR(l_pds->dcodec_pd) : -ENODATA;
+		goto dcodec_err;
+	}
+
+	ret = pm_runtime_resume_and_get(l_pds->dcodec_pd);
+	if (ret < 0)
+		goto dcodec_sync_err;
+	return l_pds;
+
+dcodec_sync_err:
+	dev_pm_domain_detach(l_pds->dcodec_pd, false);
+dcodec_err:
+	pm_runtime_put(l_pds->macro_pd);
+macro_sync_err:
+	dev_pm_domain_detach(l_pds->macro_pd, false);
+macro_err:
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(lpass_macro_pds_init);
+
+void lpass_macro_pds_exit(struct lpass_macro *pds)
+{
+	if (pds) {
+		pm_runtime_put(pds->macro_pd);
+		dev_pm_domain_detach(pds->macro_pd, false);
+		pm_runtime_put(pds->dcodec_pd);
+		dev_pm_domain_detach(pds->dcodec_pd, false);
+	}
+}
+EXPORT_SYMBOL_GPL(lpass_macro_pds_exit);
+
+void lpass_macro_set_codec_version(enum lpass_codec_version version)
+{
+	guard(mutex)(&lpass_codec_mutex);
+	lpass_codec_version = version;
+}
+EXPORT_SYMBOL_GPL(lpass_macro_set_codec_version);
+
+enum lpass_codec_version lpass_macro_get_codec_version(void)
+{
+	guard(mutex)(&lpass_codec_mutex);
+
+	return lpass_codec_version;
+}
+EXPORT_SYMBOL_GPL(lpass_macro_get_codec_version);
+
+MODULE_DESCRIPTION("Common macro driver");
+MODULE_LICENSE("GPL");