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, 191 insertions, 0 deletions

diff --git a/sound/soc/codecs/pcm1754.c b/sound/soc/codecs/pcm1754.c
new file mode 100644
index 000000000..bb15da1c2
--- /dev/null
+++ b/sound/soc/codecs/pcm1754.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PCM1754 DAC ASoC codec driver
+ *
+ * Copyright (c) 2022 Alvin Šipraga <alsi@bang-olufsen.dk>
+ * Copyright (c) 2025 Stefan Kerkmann <s.kerkmann@pengutronix.de>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+
+struct pcm1754_priv {
+	unsigned int format;
+	struct gpio_desc *gpiod_mute;
+	struct gpio_desc *gpiod_format;
+};
+
+static int pcm1754_set_dai_fmt(struct snd_soc_dai *codec_dai,
+				   unsigned int format)
+{
+	struct snd_soc_component *component = codec_dai->component;
+	struct pcm1754_priv *priv = snd_soc_component_get_drvdata(component);
+
+	priv->format = format;
+
+	return 0;
+}
+
+static int pcm1754_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *params,
+				 struct snd_soc_dai *codec_dai)
+{
+	struct snd_soc_component *component = codec_dai->component;
+	struct pcm1754_priv *priv = snd_soc_component_get_drvdata(component);
+	int format;
+
+	switch (priv->format & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_RIGHT_J:
+		switch (params_width(params)) {
+		case 16:
+			format = 1;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case SND_SOC_DAIFMT_I2S:
+		switch (params_width(params)) {
+		case 16:
+			fallthrough;
+		case 24:
+			format = 0;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	default:
+		dev_err(component->dev, "Invalid DAI format\n");
+		return -EINVAL;
+	}
+
+	gpiod_set_value_cansleep(priv->gpiod_format, format);
+
+	return 0;
+}
+
+static int pcm1754_mute_stream(struct snd_soc_dai *dai, int mute, int stream)
+{
+	struct pcm1754_priv *priv = snd_soc_component_get_drvdata(dai->component);
+
+	gpiod_set_value_cansleep(priv->gpiod_mute, mute);
+
+	return 0;
+}
+
+static const u64 pcm1754_selectable_formats =
+	SND_SOC_POSSIBLE_DAIFMT_I2S	|
+	SND_SOC_POSSIBLE_DAIFMT_RIGHT_J;
+
+static const struct snd_soc_dai_ops pcm1754_dai_ops = {
+	.set_fmt = pcm1754_set_dai_fmt,
+	.hw_params = pcm1754_hw_params,
+	.mute_stream = pcm1754_mute_stream,
+	.auto_selectable_formats = &pcm1754_selectable_formats,
+	.num_auto_selectable_formats = 1,
+};
+
+static const struct snd_soc_dai_driver pcm1754_dai = {
+	.name = "pcm1754",
+	.playback = {
+		.stream_name	= "Playback",
+		.channels_min	= 2,
+		.channels_max	= 2,
+		.rates		= SNDRV_PCM_RATE_CONTINUOUS,
+		.rate_min	= 5000,
+		.rate_max	= 200000,
+		.formats	= SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_LE
+	},
+	.ops = &pcm1754_dai_ops,
+};
+
+static const struct snd_soc_dapm_widget pcm1754_dapm_widgets[] = {
+	SND_SOC_DAPM_REGULATOR_SUPPLY("VCC", 0, 0),
+
+	SND_SOC_DAPM_DAC("DAC1", "Channel 1 Playback", SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_DAC("DAC2", "Channel 2 Playback", SND_SOC_NOPM, 0, 0),
+
+	SND_SOC_DAPM_OUTPUT("VOUTL"),
+	SND_SOC_DAPM_OUTPUT("VOUTR"),
+};
+
+static const struct snd_soc_dapm_route pcm1754_dapm_routes[] = {
+	{ "DAC1", NULL, "Playback" },
+	{ "DAC2", NULL, "Playback" },
+
+	{ "DAC1", NULL, "VCC" },
+	{ "DAC2", NULL, "VCC" },
+
+	{ "VOUTL", NULL, "DAC1" },
+	{ "VOUTR", NULL, "DAC2" },
+};
+
+static const struct snd_soc_component_driver soc_component_dev_pcm1754 = {
+	.dapm_widgets = pcm1754_dapm_widgets,
+	.num_dapm_widgets = ARRAY_SIZE(pcm1754_dapm_widgets),
+	.dapm_routes = pcm1754_dapm_routes,
+	.num_dapm_routes = ARRAY_SIZE(pcm1754_dapm_routes),
+};
+
+static int pcm1754_probe(struct platform_device *pdev)
+{
+	struct pcm1754_priv *priv;
+	struct device *dev = &pdev->dev;
+	struct snd_soc_dai_driver *dai_drv;
+	int ret;
+
+	dai_drv = devm_kmemdup(dev, &pcm1754_dai, sizeof(*dai_drv), GFP_KERNEL);
+	if (!dai_drv)
+		return -ENOMEM;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->gpiod_mute = devm_gpiod_get_optional(dev, "mute", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->gpiod_mute))
+		return dev_err_probe(dev, PTR_ERR(priv->gpiod_mute),
+					 "failed to get mute gpio");
+
+	priv->gpiod_format = devm_gpiod_get_optional(dev, "format", GPIOD_OUT_LOW);
+	if (IS_ERR(priv->gpiod_format))
+		return dev_err_probe(dev, PTR_ERR(priv->gpiod_format),
+					 "failed to get format gpio");
+
+	dev_set_drvdata(dev, priv);
+
+	ret = devm_snd_soc_register_component(
+		&pdev->dev, &soc_component_dev_pcm1754, dai_drv, 1);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to register");
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id pcm1754_of_match[] = {
+	{ .compatible = "ti,pcm1754" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pcm1754_of_match);
+#endif
+
+static struct platform_driver pcm1754_codec_driver = {
+	.driver = {
+		.name = "pcm1754-codec",
+		.of_match_table = of_match_ptr(pcm1754_of_match),
+	},
+	.probe = pcm1754_probe,
+};
+
+module_platform_driver(pcm1754_codec_driver);
+
+MODULE_DESCRIPTION("ASoC PCM1754 driver");
+MODULE_AUTHOR("Alvin Šipraga <alsi@bang-olufsen.dk>");
+MODULE_AUTHOR("Stefan Kerkmann <s.kerkmann@pengutronix.de>");
+MODULE_LICENSE("GPL");