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, 78 insertions, 0 deletions

diff --git a/sound/soc/codecs/wm8727.c b/sound/soc/codecs/wm8727.c
new file mode 100644
index 000000000..d6b0a570d
--- /dev/null
+++ b/sound/soc/codecs/wm8727.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * wm8727.c
+ *
+ *  Created on: 15-Oct-2009
+ *      Author: neil.jones@imgtec.com
+ *
+ * Copyright (C) 2009 Imagination Technologies Ltd.
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/initval.h>
+#include <sound/soc.h>
+
+static const struct snd_soc_dapm_widget wm8727_dapm_widgets[] = {
+SND_SOC_DAPM_OUTPUT("VOUTL"),
+SND_SOC_DAPM_OUTPUT("VOUTR"),
+};
+
+static const struct snd_soc_dapm_route wm8727_dapm_routes[] = {
+	{ "VOUTL", NULL, "Playback" },
+	{ "VOUTR", NULL, "Playback" },
+};
+
+/*
+ * Note this is a simple chip with no configuration interface, sample rate is
+ * determined automatically by examining the Master clock and Bit clock ratios
+ */
+#define WM8727_RATES  (SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 |\
+			SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000 |\
+			SNDRV_PCM_RATE_192000)
+
+static struct snd_soc_dai_driver wm8727_dai = {
+	.name = "wm8727-hifi",
+	.playback = {
+		.stream_name = "Playback",
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = WM8727_RATES,
+		.formats = SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_LE,
+		},
+};
+
+static const struct snd_soc_component_driver soc_component_dev_wm8727 = {
+	.dapm_widgets		= wm8727_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(wm8727_dapm_widgets),
+	.dapm_routes		= wm8727_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(wm8727_dapm_routes),
+	.idle_bias_on		= 1,
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+};
+
+static int wm8727_probe(struct platform_device *pdev)
+{
+	return devm_snd_soc_register_component(&pdev->dev,
+			&soc_component_dev_wm8727, &wm8727_dai, 1);
+}
+
+static struct platform_driver wm8727_codec_driver = {
+	.driver = {
+			.name = "wm8727",
+	},
+
+	.probe = wm8727_probe,
+};
+
+module_platform_driver(wm8727_codec_driver);
+
+MODULE_DESCRIPTION("ASoC wm8727 driver");
+MODULE_AUTHOR("Neil Jones");
+MODULE_LICENSE("GPL");