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, 166 insertions, 0 deletions

diff --git a/sound/soc/codecs/pcm3008.c b/sound/soc/codecs/pcm3008.c
new file mode 100644
index 000000000..d3d2e7f40
--- /dev/null
+++ b/sound/soc/codecs/pcm3008.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ALSA Soc PCM3008 codec support
+ *
+ * Author:	Hugo Villeneuve
+ * Copyright (C) 2008 Lyrtech inc
+ *
+ * Based on AC97 Soc codec, original copyright follow:
+ * Copyright 2005 Wolfson Microelectronics PLC.
+ *
+ * Generic PCM3008 support.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/initval.h>
+#include <sound/soc.h>
+
+struct pcm3008 {
+	struct gpio_desc *dem0_pin;
+	struct gpio_desc *dem1_pin;
+	struct gpio_desc *pdad_pin;
+	struct gpio_desc *pdda_pin;
+};
+
+static int pcm3008_dac_ev(struct snd_soc_dapm_widget *w,
+			  struct snd_kcontrol *kcontrol,
+			  int event)
+{
+	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
+	struct pcm3008 *pcm = component->dev->platform_data;
+
+	gpiod_set_value_cansleep(pcm->pdda_pin,
+				 SND_SOC_DAPM_EVENT_ON(event));
+
+	return 0;
+}
+
+static int pcm3008_adc_ev(struct snd_soc_dapm_widget *w,
+			  struct snd_kcontrol *kcontrol,
+			  int event)
+{
+	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
+	struct pcm3008 *pcm = component->dev->platform_data;
+
+	gpiod_set_value_cansleep(pcm->pdad_pin,
+				 SND_SOC_DAPM_EVENT_ON(event));
+
+	return 0;
+}
+
+static const struct snd_soc_dapm_widget pcm3008_dapm_widgets[] = {
+SND_SOC_DAPM_INPUT("VINL"),
+SND_SOC_DAPM_INPUT("VINR"),
+
+SND_SOC_DAPM_DAC_E("DAC", NULL, SND_SOC_NOPM, 0, 0, pcm3008_dac_ev,
+		   SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_POST_PMD),
+SND_SOC_DAPM_ADC_E("ADC", NULL, SND_SOC_NOPM, 0, 0, pcm3008_adc_ev,
+		   SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_POST_PMD),
+
+SND_SOC_DAPM_OUTPUT("VOUTL"),
+SND_SOC_DAPM_OUTPUT("VOUTR"),
+};
+
+static const struct snd_soc_dapm_route pcm3008_dapm_routes[] = {
+	{ "PCM3008 Capture", NULL, "ADC" },
+	{ "ADC", NULL, "VINL" },
+	{ "ADC", NULL, "VINR" },
+
+	{ "DAC", NULL, "PCM3008 Playback" },
+	{ "VOUTL", NULL, "DAC" },
+	{ "VOUTR", NULL, "DAC" },
+};
+
+#define PCM3008_RATES (SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 |	\
+		       SNDRV_PCM_RATE_48000)
+
+static struct snd_soc_dai_driver pcm3008_dai = {
+	.name = "pcm3008-hifi",
+	.playback = {
+		.stream_name = "PCM3008 Playback",
+		.channels_min = 1,
+		.channels_max = 2,
+		.rates = PCM3008_RATES,
+		.formats = SNDRV_PCM_FMTBIT_S16_LE,
+	},
+	.capture = {
+		.stream_name = "PCM3008 Capture",
+		.channels_min = 1,
+		.channels_max = 2,
+		.rates = PCM3008_RATES,
+		.formats = SNDRV_PCM_FMTBIT_S16_LE,
+	},
+};
+
+static const struct snd_soc_component_driver soc_component_dev_pcm3008 = {
+	.dapm_widgets		= pcm3008_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(pcm3008_dapm_widgets),
+	.dapm_routes		= pcm3008_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(pcm3008_dapm_routes),
+	.idle_bias_on		= 1,
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+};
+
+static int pcm3008_codec_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pcm3008 *pcm;
+
+	pcm = devm_kzalloc(dev, sizeof(*pcm), GFP_KERNEL);
+	if (!pcm)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, pcm);
+
+	/* DEM1  DEM0  DE-EMPHASIS_MODE
+	 * Low   Low   De-emphasis 44.1 kHz ON
+	 * Low   High  De-emphasis OFF
+	 * High  Low   De-emphasis 48 kHz ON
+	 * High  High  De-emphasis 32 kHz ON
+	 */
+
+	/* Configure DEM0 GPIO (turning OFF DAC De-emphasis). */
+	pcm->dem0_pin = devm_gpiod_get(dev, "dem0", GPIOD_OUT_HIGH);
+	if (IS_ERR(pcm->dem0_pin))
+		return PTR_ERR(pcm->dem0_pin);
+
+	/* Configure DEM1 GPIO (turning OFF DAC De-emphasis). */
+	pcm->dem1_pin = devm_gpiod_get(dev, "dem1", GPIOD_OUT_LOW);
+	if (IS_ERR(pcm->dem1_pin))
+		return PTR_ERR(pcm->dem1_pin);
+
+	/* Configure PDAD GPIO. */
+	pcm->pdad_pin = devm_gpiod_get(dev, "pdad", GPIOD_OUT_LOW);
+	if (IS_ERR(pcm->pdad_pin))
+		return PTR_ERR(pcm->pdad_pin);
+
+	/* Configure PDDA GPIO. */
+	pcm->pdda_pin = devm_gpiod_get(dev, "pdda", GPIOD_OUT_LOW);
+	if (IS_ERR(pcm->pdda_pin))
+		return PTR_ERR(pcm->pdda_pin);
+
+	return devm_snd_soc_register_component(dev,
+			&soc_component_dev_pcm3008, &pcm3008_dai, 1);
+}
+
+MODULE_ALIAS("platform:pcm3008-codec");
+
+static struct platform_driver pcm3008_codec_driver = {
+	.probe		= pcm3008_codec_probe,
+	.driver		= {
+		.name	= "pcm3008-codec",
+	},
+};
+
+module_platform_driver(pcm3008_codec_driver);
+
+MODULE_DESCRIPTION("Soc PCM3008 driver");
+MODULE_AUTHOR("Hugo Villeneuve");
+MODULE_LICENSE("GPL");