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, 104 insertions, 0 deletions

diff --git a/sound/soc/codecs/aw8738.c b/sound/soc/codecs/aw8738.c
new file mode 100644
index 000000000..0fe8af160
--- /dev/null
+++ b/sound/soc/codecs/aw8738.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <sound/soc.h>
+
+struct aw8738_priv {
+	struct gpio_desc *gpiod_mode;
+	unsigned int mode;
+};
+
+static int aw8738_drv_event(struct snd_soc_dapm_widget *w,
+			    struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_component *c = snd_soc_dapm_to_component(w->dapm);
+	struct aw8738_priv *aw = snd_soc_component_get_drvdata(c);
+	int i;
+
+	switch (event) {
+	case SND_SOC_DAPM_POST_PMU:
+		for (i = 0; i < aw->mode; i++) {
+			gpiod_set_value_cansleep(aw->gpiod_mode, 0);
+			udelay(2);
+			gpiod_set_value_cansleep(aw->gpiod_mode, 1);
+			udelay(2);
+		}
+		msleep(40);
+		break;
+	case SND_SOC_DAPM_PRE_PMD:
+		gpiod_set_value_cansleep(aw->gpiod_mode, 0);
+		usleep_range(1000, 2000);
+		break;
+	default:
+		WARN(1, "Unexpected event");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_dapm_widget aw8738_dapm_widgets[] = {
+	SND_SOC_DAPM_INPUT("IN"),
+	SND_SOC_DAPM_OUT_DRV_E("DRV", SND_SOC_NOPM, 0, 0, NULL, 0, aw8738_drv_event,
+			       SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_PRE_PMD),
+	SND_SOC_DAPM_OUTPUT("OUT"),
+};
+
+static const struct snd_soc_dapm_route aw8738_dapm_routes[] = {
+	{ "DRV", NULL, "IN" },
+	{ "OUT", NULL, "DRV" },
+};
+
+static const struct snd_soc_component_driver aw8738_component_driver = {
+	.dapm_widgets = aw8738_dapm_widgets,
+	.num_dapm_widgets = ARRAY_SIZE(aw8738_dapm_widgets),
+	.dapm_routes = aw8738_dapm_routes,
+	.num_dapm_routes = ARRAY_SIZE(aw8738_dapm_routes),
+};
+
+static int aw8738_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct aw8738_priv *aw;
+	int ret;
+
+	aw = devm_kzalloc(dev, sizeof(*aw), GFP_KERNEL);
+	if (!aw)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, aw);
+
+	aw->gpiod_mode = devm_gpiod_get(dev, "mode", GPIOD_OUT_LOW);
+	if (IS_ERR(aw->gpiod_mode))
+		return dev_err_probe(dev, PTR_ERR(aw->gpiod_mode),
+				     "Failed to get 'mode' gpio");
+
+	ret = device_property_read_u32(dev, "awinic,mode", &aw->mode);
+	if (ret)
+		return -EINVAL;
+
+	return devm_snd_soc_register_component(&pdev->dev,
+					       &aw8738_component_driver,
+					       NULL, 0);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id aw8738_of_match[] = {
+	{ .compatible = "awinic,aw8738" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, aw8738_of_match);
+#endif
+
+static struct platform_driver aw8738_driver = {
+	.probe	= aw8738_probe,
+	.driver = {
+		.name = "aw8738",
+		.of_match_table = of_match_ptr(aw8738_of_match),
+	},
+};
+module_platform_driver(aw8738_driver);
+
+MODULE_DESCRIPTION("Awinic AW8738 Amplifier Driver");
+MODULE_LICENSE("GPL v2");