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, 149 insertions, 0 deletions

diff --git a/sound/soc/codecs/cq93vc.c b/sound/soc/codecs/cq93vc.c
new file mode 100644
index 000000000..32b6a417d
--- /dev/null
+++ b/sound/soc/codecs/cq93vc.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ALSA SoC CQ0093 Voice Codec Driver for DaVinci platforms
+ *
+ * Copyright (C) 2010 Texas Instruments, Inc
+ *
+ * Author: Miguel Aguilar <miguel.aguilar@ridgerun.com>
+ */
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/mfd/davinci_voicecodec.h>
+#include <linux/spi/spi.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/initval.h>
+
+static const struct snd_kcontrol_new cq93vc_snd_controls[] = {
+	SOC_SINGLE("PGA Capture Volume", DAVINCI_VC_REG05, 0, 0x03, 0),
+	SOC_SINGLE("Mono DAC Playback Volume", DAVINCI_VC_REG09, 0, 0x3f, 0),
+};
+
+static int cq93vc_mute(struct snd_soc_dai *dai, int mute, int direction)
+{
+	struct snd_soc_component *component = dai->component;
+	u8 reg;
+
+	if (mute)
+		reg = DAVINCI_VC_REG09_MUTE;
+	else
+		reg = 0;
+
+	snd_soc_component_update_bits(component, DAVINCI_VC_REG09, DAVINCI_VC_REG09_MUTE,
+			    reg);
+
+	return 0;
+}
+
+static int cq93vc_set_dai_sysclk(struct snd_soc_dai *codec_dai,
+				 int clk_id, unsigned int freq, int dir)
+{
+	switch (freq) {
+	case 22579200:
+	case 27000000:
+	case 33868800:
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int cq93vc_set_bias_level(struct snd_soc_component *component,
+				enum snd_soc_bias_level level)
+{
+	switch (level) {
+	case SND_SOC_BIAS_ON:
+		snd_soc_component_write(component, DAVINCI_VC_REG12,
+			     DAVINCI_VC_REG12_POWER_ALL_ON);
+		break;
+	case SND_SOC_BIAS_PREPARE:
+		break;
+	case SND_SOC_BIAS_STANDBY:
+		snd_soc_component_write(component, DAVINCI_VC_REG12,
+			     DAVINCI_VC_REG12_POWER_ALL_OFF);
+		break;
+	case SND_SOC_BIAS_OFF:
+		/* force all power off */
+		snd_soc_component_write(component, DAVINCI_VC_REG12,
+			     DAVINCI_VC_REG12_POWER_ALL_OFF);
+		break;
+	}
+
+	return 0;
+}
+
+#define CQ93VC_RATES	(SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000)
+#define CQ93VC_FORMATS	(SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
+
+static const struct snd_soc_dai_ops cq93vc_dai_ops = {
+	.mute_stream	= cq93vc_mute,
+	.set_sysclk	= cq93vc_set_dai_sysclk,
+	.no_capture_mute = 1,
+};
+
+static struct snd_soc_dai_driver cq93vc_dai = {
+	.name = "cq93vc-hifi",
+	.playback = {
+		.stream_name = "Playback",
+		.channels_min = 1,
+		.channels_max = 2,
+		.rates = CQ93VC_RATES,
+		.formats = CQ93VC_FORMATS,},
+	.capture = {
+		.stream_name = "Capture",
+		.channels_min = 1,
+		.channels_max = 2,
+		.rates = CQ93VC_RATES,
+		.formats = CQ93VC_FORMATS,},
+	.ops = &cq93vc_dai_ops,
+};
+
+static int cq93vc_probe(struct snd_soc_component *component)
+{
+	struct davinci_vc *davinci_vc = component->dev->platform_data;
+
+	snd_soc_component_init_regmap(component, davinci_vc->regmap);
+
+	return 0;
+}
+
+static const struct snd_soc_component_driver soc_component_dev_cq93vc = {
+	.set_bias_level		= cq93vc_set_bias_level,
+	.probe			= cq93vc_probe,
+	.controls		= cq93vc_snd_controls,
+	.num_controls		= ARRAY_SIZE(cq93vc_snd_controls),
+	.idle_bias_on		= 1,
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+};
+
+static int cq93vc_platform_probe(struct platform_device *pdev)
+{
+	return devm_snd_soc_register_component(&pdev->dev,
+			&soc_component_dev_cq93vc, &cq93vc_dai, 1);
+}
+
+static struct platform_driver cq93vc_codec_driver = {
+	.driver = {
+			.name = "cq93vc-codec",
+	},
+
+	.probe = cq93vc_platform_probe,
+};
+
+module_platform_driver(cq93vc_codec_driver);
+
+MODULE_DESCRIPTION("Texas Instruments DaVinci ASoC CQ0093 Voice Codec Driver");
+MODULE_AUTHOR("Miguel Aguilar");
+MODULE_LICENSE("GPL");